2019-08-20 02:16:12

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 00/16] Secure Virtual Machine Enablement

Hello,

This is a minor update of this patch series. It addresses review comments
made to v3. Details are in the changelog. The sysfs patch is updated and
included here but as I mentioned earlier can be postponed. It is marked
RFC for that reason.

As with the previous version, the patch introducing ucall_norets() (patch 1)
and the one adding documentation on the Ultravisor (patch 15) are copied
from v5 of Claudio Carvalho's KVM on Ultravisor series and don't yet address
the review comments made there. They are included here so that this series
can stand on its own.

The patches apply on top of v4 of the <asm/mem_encrypt.h> cleanup series:

https://lore.kernel.org/linuxppc-dev/[email protected]/

Everything is available in branch ultravisor-secure-vm (applied on top of
today's powerpc/next) at this repo:

https://github.com/bauermann/linux.git

Original cover letter below, and changelog at the bottom:

This series enables Secure Virtual Machines (SVMs) on powerpc. SVMs use the
Protected Execution Facility (PEF) and request to be migrated to secure
memory during prom_init() so by default all of their memory is inaccessible
to the hypervisor. There is an Ultravisor call that the VM can use to
request certain pages to be made accessible to (or shared with) the
hypervisor.

The objective of these patches is to have the guest perform this request
for buffers that need to be accessed by the hypervisor such as the LPPACAs,
the SWIOTLB memory and the Debug Trace Log.

Patch 3 ("powerpc: Add support for adding an ESM blob to the zImage
wrapper") is posted as RFC because we are still finalizing the details on
how the ESM blob will be passed along with the kernel. All other patches are
(hopefully) in upstreamable shape and don't depend on this patch.

Unfortunately this series still doesn't enable the use of virtio devices in
the secure guest. This support depends on a discussion that is currently
ongoing with the virtio community:

https://lore.kernel.org/linuxppc-dev/[email protected]/

I was able to test it using Claudio's patches in the host kernel, booting
normally using an initramfs for the root filesystem.

This is the command used to start up the guest with QEMU 4.0:

qemu-system-ppc64 \
-nodefaults \
-cpu host \
-machine pseries,accel=kvm,kvm-type=HV,cap-htm=off,cap-cfpc=broken,cap-sbbc=broken,cap-ibs=broken \
-display none \
-serial mon:stdio \
-smp 1 \
-m 4G \
-kernel /root/bauermann/vmlinux \
-initrd /root/bauermann/fs_small.cpio \
-append 'debug'

Changelog

Since v3:

- Patch "powerpc/kernel: Add ucall_norets() ultravisor call handler"
- Use updated commit message from Claudio Carvalho's KVM series v5.

- Patch "powerpc: Introduce the MSR_S bit"
- Use updated commit message from Claudio Carvalho.

- Patch "powerpc/pseries/svm: Use shared memory for LPPACA structures"
- Changed copyright year in <asm/svm.h> to 2018. Suggested by Michael
Ellerman.

- Patch "powerpc/pseries/svm: Use shared memory for Debug Trace Log (DTL)"
- Changed copyright year in svm.c to 2018. Suggested by Michael Ellerman.

- Patch "powerpc/pseries/svm: Export guest SVM status to user space via sysfs"
- Changed to check MSR_S on the current CPU. Suggested by Michael Ellerman.
- Added documentation for new sysfs file. Suggested by Michael Ellerman.

- Patch "powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests"
- Changed to only call set_pci_dma_ops() on non-secure guests. Suggested
by Christoph Hellwig.

- Patch "powerpc/pseries/svm: Force SWIOTLB for secure guests"
- Changed copyright year in <asm/mem_encrypt.h> to 2018. Suggested by
Michael Ellerman.

- Patch "Documentation/powerpc: Ultravisor API"
- Use updated patch from Claudio Carvalho's KVM series v5.

Since v2:

- Patch "powerpc/kernel: Add ucall_norets() ultravisor call handler"
- Borrowed unchanged from Claudio's "kvmppc: Paravirtualize KVM to support
ultravisor" series.

- Patch "powerpc/prom_init: Add the ESM call to prom_init"
- Briefly mention in the commit message why we pass the kernel base address
and FDT to the Enter Secure Mode ultracall. Suggested by Alexey
Kardashevskiy.
- Use enter_secure_mode() version provided by Segher Boessenkool.

- Patch "powerpc/pseries/svm: Add helpers for UV_SHARE_PAGE and UV_UNSHARE_PAGE"
- Use ucall_norets() which doesn't need to be passed a return buffer.
Suggested by Alexey Kardashevskiy.

- Patch "powerpc: Introduce the MSR_S bit"
- Moved from Claudio's "kvmppc: Paravirtualize KVM to support ultravisor"
series to this series.

- Patch "Documentation/powerpc: Ultravisor API"
- New patch from Sukadev Bhattiprolu. Will also appear on Claudio's
kvmppc series.

Since v1:

- Patch "powerpc/pseries: Introduce option to build secure virtual machines"
- Dropped redundant "default n" from CONFIG_PPC_SVM. Suggested by Christoph
Hellwig.

- Patch "powerpc: Add support for adding an ESM blob to the zImage wrapper"
- Renamed prom_rtas_os_term_hcall() to prom_rtas_hcall(). Suggested by Alexey
Kardashevskiy.
- In prom_rtas_hcall(), changed prom_printf() calls to prom_debug(), and
use H_RTAS constant instead of raw value.
- Changed enter_secure_mode() to new ABI passing ucall number in r3.
Also changed it to accept kbase argument instead of ESM blob address.
- Changed setup_secure_guest() to only make the ESM ultracall if svm=1 was
passed on the kernel command line.

- Patch "powerpc/pseries/svm: Unshare all pages before kexecing a new kernel"
- New patch from Ram Pai.

- Patch "powerpc/pseries/svm: Force SWIOTLB for secure guests"
- No need to define sme_me_mask, sme_active() and sev_active() anymore.
- Add definitions for mem_encrypt_active() and force_dma_unencrypted().
- Select ARCH_HAS_FORCE_DMA_UNENCRYPTED in CONFIG_PPC_SVM.

Anshuman Khandual (3):
powerpc/pseries/svm: Use shared memory for LPPACA structures
powerpc/pseries/svm: Use shared memory for Debug Trace Log (DTL)
powerpc/pseries/svm: Force SWIOTLB for secure guests

Benjamin Herrenschmidt (1):
powerpc: Add support for adding an ESM blob to the zImage wrapper

Claudio Carvalho (1):
powerpc/kernel: Add ucall_norets() ultravisor call handler

Ram Pai (3):
powerpc/prom_init: Add the ESM call to prom_init
powerpc/pseries/svm: Add helpers for UV_SHARE_PAGE and UV_UNSHARE_PAGE
powerpc/pseries/svm: Unshare all pages before kexecing a new kernel

Ryan Grimm (2):
powerpc/pseries/svm: Export guest SVM status to user space via sysfs
powerpc/configs: Enable secure guest support in pseries and ppc64
defconfigs

Sukadev Bhattiprolu (3):
powerpc: Introduce the MSR_S bit
powerpc/pseries/svm: Disable doorbells in SVM guests
Documentation/powerpc: Ultravisor API

Thiago Jung Bauermann (3):
powerpc/pseries: Introduce option to build secure virtual machines
powerpc/pseries: Add and use LPPACA_SIZE constant
powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests

.../ABI/testing/sysfs-devices-system-cpu | 10 +
.../admin-guide/kernel-parameters.txt | 5 +
Documentation/powerpc/ultravisor.rst | 1055 +++++++++++++++++
arch/powerpc/boot/main.c | 41 +
arch/powerpc/boot/ops.h | 2 +
arch/powerpc/boot/wrapper | 24 +-
arch/powerpc/boot/zImage.lds.S | 8 +
arch/powerpc/configs/ppc64_defconfig | 1 +
arch/powerpc/configs/pseries_defconfig | 1 +
arch/powerpc/include/asm/asm-prototypes.h | 11 +
arch/powerpc/include/asm/mem_encrypt.h | 26 +
arch/powerpc/include/asm/reg.h | 3 +
arch/powerpc/include/asm/svm.h | 31 +
arch/powerpc/include/asm/ultravisor-api.h | 29 +
arch/powerpc/include/asm/ultravisor.h | 29 +
arch/powerpc/kernel/Makefile | 3 +
arch/powerpc/kernel/machine_kexec_64.c | 9 +
arch/powerpc/kernel/paca.c | 52 +-
arch/powerpc/kernel/prom_init.c | 96 ++
arch/powerpc/kernel/sysfs.c | 20 +
arch/powerpc/kernel/ucall.S | 20 +
arch/powerpc/platforms/pseries/Kconfig | 14 +
arch/powerpc/platforms/pseries/Makefile | 1 +
arch/powerpc/platforms/pseries/iommu.c | 11 +-
arch/powerpc/platforms/pseries/setup.c | 5 +-
arch/powerpc/platforms/pseries/smp.c | 3 +-
arch/powerpc/platforms/pseries/svm.c | 85 ++
27 files changed, 1584 insertions(+), 11 deletions(-)
create mode 100644 Documentation/powerpc/ultravisor.rst
create mode 100644 arch/powerpc/include/asm/mem_encrypt.h
create mode 100644 arch/powerpc/include/asm/svm.h
create mode 100644 arch/powerpc/include/asm/ultravisor-api.h
create mode 100644 arch/powerpc/include/asm/ultravisor.h
create mode 100644 arch/powerpc/kernel/ucall.S
create mode 100644 arch/powerpc/platforms/pseries/svm.c


2019-08-20 02:17:04

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 10/16] powerpc/pseries/svm: Unshare all pages before kexecing a new kernel

From: Ram Pai <[email protected]>

A new kernel deserves a clean slate. Any pages shared with the hypervisor
is unshared before invoking the new kernel. However there are exceptions.
If the new kernel is invoked to dump the current kernel, or if there is a
explicit request to preserve the state of the current kernel, unsharing
of pages is skipped.

NOTE: While testing crashkernel, make sure at least 256M is reserved for
crashkernel. Otherwise SWIOTLB allocation will fail and crash kernel will
fail to boot.

Signed-off-by: Ram Pai <[email protected]>
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
arch/powerpc/include/asm/ultravisor-api.h | 1 +
arch/powerpc/include/asm/ultravisor.h | 5 +++++
arch/powerpc/kernel/machine_kexec_64.c | 9 +++++++++
3 files changed, 15 insertions(+)

diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
index 142b0576b89f..7e69c364bde0 100644
--- a/arch/powerpc/include/asm/ultravisor-api.h
+++ b/arch/powerpc/include/asm/ultravisor-api.h
@@ -24,5 +24,6 @@
#define UV_ESM 0xF110
#define UV_SHARE_PAGE 0xF130
#define UV_UNSHARE_PAGE 0xF134
+#define UV_UNSHARE_ALL_PAGES 0xF140

#endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h
index a930aec8c1e3..e6f8a2b96694 100644
--- a/arch/powerpc/include/asm/ultravisor.h
+++ b/arch/powerpc/include/asm/ultravisor.h
@@ -21,4 +21,9 @@ static inline int uv_unshare_page(u64 pfn, u64 npages)
return ucall_norets(UV_UNSHARE_PAGE, pfn, npages);
}

+static inline int uv_unshare_all_pages(void)
+{
+ return ucall_norets(UV_UNSHARE_ALL_PAGES);
+}
+
#endif /* _ASM_POWERPC_ULTRAVISOR_H */
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 18481b0e2788..04a7cba58eff 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -29,6 +29,8 @@
#include <asm/smp.h>
#include <asm/hw_breakpoint.h>
#include <asm/asm-prototypes.h>
+#include <asm/svm.h>
+#include <asm/ultravisor.h>

int default_machine_kexec_prepare(struct kimage *image)
{
@@ -327,6 +329,13 @@ void default_machine_kexec(struct kimage *image)
#ifdef CONFIG_PPC_PSERIES
kexec_paca.lppaca_ptr = NULL;
#endif
+
+ if (is_secure_guest() && !(image->preserve_context ||
+ image->type == KEXEC_TYPE_CRASH)) {
+ uv_unshare_all_pages();
+ printk("kexec: Unshared all shared pages.\n");
+ }
+
paca_ptrs[kexec_paca.paca_index] = &kexec_paca;

setup_paca(&kexec_paca);

2019-08-20 02:17:38

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 04/16] powerpc/prom_init: Add the ESM call to prom_init

From: Ram Pai <[email protected]>

Make the Enter-Secure-Mode (ESM) ultravisor call to switch the VM to secure
mode. Pass kernel base address and FDT address so that the Ultravisor is
able to verify the integrity of the VM using information from the ESM blob.

Add "svm=" command line option to turn on switching to secure mode.

Signed-off-by: Ram Pai <[email protected]>
[ andmike: Generate an RTAS os-term hcall when the ESM ucall fails. ]
Signed-off-by: Michael Anderson <[email protected]>
[ bauerman: Cleaned up the code a bit. ]
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
.../admin-guide/kernel-parameters.txt | 5 +
arch/powerpc/include/asm/ultravisor-api.h | 3 +
arch/powerpc/kernel/prom_init.c | 96 +++++++++++++++++++
3 files changed, 104 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7ccd158b3894..231a008b7961 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4620,6 +4620,11 @@
/sys/power/pm_test). Only available when CONFIG_PM_DEBUG
is set. Default value is 5.

+ svm= [PPC]
+ Format: { on | off | y | n | 1 | 0 }
+ This parameter controls use of the Protected
+ Execution Facility on pSeries.
+
swapaccount=[0|1]
[KNL] Enable accounting of swap in memory resource
controller if no parameter or 1 is given or disable
diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
index 88ffa78f9d61..d3503d1f447e 100644
--- a/arch/powerpc/include/asm/ultravisor-api.h
+++ b/arch/powerpc/include/asm/ultravisor-api.h
@@ -20,4 +20,7 @@
#define U_PARAMETER H_PARAMETER
#define U_SUCCESS H_SUCCESS

+/* opcodes */
+#define UV_ESM 0xF110
+
#endif /* _ASM_POWERPC_ULTRAVISOR_API_H */
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 514707ef6779..74f70f90eff0 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -40,6 +40,7 @@
#include <asm/sections.h>
#include <asm/machdep.h>
#include <asm/asm-prototypes.h>
+#include <asm/ultravisor-api.h>

#include <linux/linux_logo.h>

@@ -171,6 +172,10 @@ static bool __prombss prom_radix_disable;
static bool __prombss prom_xive_disable;
#endif

+#ifdef CONFIG_PPC_SVM
+static bool __prombss prom_svm_enable;
+#endif
+
struct platform_support {
bool hash_mmu;
bool radix_mmu;
@@ -812,6 +817,17 @@ static void __init early_cmdline_parse(void)
prom_debug("XIVE disabled from cmdline\n");
}
#endif /* CONFIG_PPC_PSERIES */
+
+#ifdef CONFIG_PPC_SVM
+ opt = prom_strstr(prom_cmd_line, "svm=");
+ if (opt) {
+ bool val;
+
+ opt += sizeof("svm=") - 1;
+ if (!prom_strtobool(opt, &val))
+ prom_svm_enable = val;
+ }
+#endif /* CONFIG_PPC_SVM */
}

#ifdef CONFIG_PPC_PSERIES
@@ -1712,6 +1728,43 @@ static void __init prom_close_stdin(void)
}
}

+#ifdef CONFIG_PPC_SVM
+static int prom_rtas_hcall(uint64_t args)
+{
+ register uint64_t arg1 asm("r3") = H_RTAS;
+ register uint64_t arg2 asm("r4") = args;
+
+ asm volatile("sc 1\n" : "=r" (arg1) :
+ "r" (arg1),
+ "r" (arg2) :);
+ return arg1;
+}
+
+static struct rtas_args __prombss os_term_args;
+
+static void __init prom_rtas_os_term(char *str)
+{
+ phandle rtas_node;
+ __be32 val;
+ u32 token;
+
+ prom_debug("%s: start...\n", __func__);
+ rtas_node = call_prom("finddevice", 1, 1, ADDR("/rtas"));
+ prom_debug("rtas_node: %x\n", rtas_node);
+ if (!PHANDLE_VALID(rtas_node))
+ return;
+
+ val = 0;
+ prom_getprop(rtas_node, "ibm,os-term", &val, sizeof(val));
+ token = be32_to_cpu(val);
+ prom_debug("ibm,os-term: %x\n", token);
+ if (token == 0)
+ prom_panic("Could not get token for ibm,os-term\n");
+ os_term_args.token = cpu_to_be32(token);
+ prom_rtas_hcall((uint64_t)&os_term_args);
+}
+#endif /* CONFIG_PPC_SVM */
+
/*
* Allocate room for and instantiate RTAS
*/
@@ -3168,6 +3221,46 @@ static void unreloc_toc(void)
#endif
#endif

+#ifdef CONFIG_PPC_SVM
+/*
+ * Perform the Enter Secure Mode ultracall.
+ */
+static int enter_secure_mode(unsigned long kbase, unsigned long fdt)
+{
+ register unsigned long r3 asm("r3") = UV_ESM;
+ register unsigned long r4 asm("r4") = kbase;
+ register unsigned long r5 asm("r5") = fdt;
+
+ asm volatile("sc 2" : "+r"(r3) : "r"(r4), "r"(r5));
+
+ return r3;
+}
+
+/*
+ * Call the Ultravisor to transfer us to secure memory if we have an ESM blob.
+ */
+static void setup_secure_guest(unsigned long kbase, unsigned long fdt)
+{
+ int ret;
+
+ if (!prom_svm_enable)
+ return;
+
+ /* Switch to secure mode. */
+ prom_printf("Switching to secure mode.\n");
+
+ ret = enter_secure_mode(kbase, fdt);
+ if (ret != U_SUCCESS) {
+ prom_printf("Returned %d from switching to secure mode.\n", ret);
+ prom_rtas_os_term("Switch to secure mode failed.\n");
+ }
+}
+#else
+static void setup_secure_guest(unsigned long kbase, unsigned long fdt)
+{
+}
+#endif /* CONFIG_PPC_SVM */
+
/*
* We enter here early on, when the Open Firmware prom is still
* handling exceptions and the MMU hash table for us.
@@ -3366,6 +3459,9 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
unreloc_toc();
#endif

+ /* Move to secure memory if we're supposed to be secure guests. */
+ setup_secure_guest(kbase, hdr);
+
__start(hdr, kbase, 0, 0, 0, 0, 0);

return 0;

2019-08-20 02:17:44

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 02/16] powerpc/pseries: Introduce option to build secure virtual machines

Introduce CONFIG_PPC_SVM to control support for secure guests and include
Ultravisor-related helpers when it is selected

Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
arch/powerpc/include/asm/asm-prototypes.h | 2 +-
arch/powerpc/kernel/Makefile | 4 +++-
arch/powerpc/platforms/pseries/Kconfig | 11 +++++++++++
3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index e698f48cbc6d..49196d35e3bb 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -36,7 +36,7 @@ void __trace_hcall_entry(unsigned long opcode, unsigned long *args);
void __trace_hcall_exit(long opcode, long retval, unsigned long *retbuf);

/* Ultravisor */
-#ifdef CONFIG_PPC_POWERNV
+#if defined(CONFIG_PPC_POWERNV) || defined(CONFIG_PPC_SVM)
long ucall_norets(unsigned long opcode, ...);
#else
static inline long ucall_norets(unsigned long opcode, ...)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index c6c4ea240b2a..ba379dfb8b83 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -156,7 +156,9 @@ endif

obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o
obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o
-obj-$(CONFIG_PPC_POWERNV) += ucall.o
+ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
+obj-y += ucall.o
+endif

# Disable GCOV, KCOV & sanitizers in odd or sensitive code
GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index f7b484f55553..d09deb05bb66 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -145,3 +145,14 @@ config PAPR_SCM
tristate "Support for the PAPR Storage Class Memory interface"
help
Enable access to hypervisor provided storage class memory.
+
+config PPC_SVM
+ bool "Secure virtual machine (SVM) support for POWER"
+ depends on PPC_PSERIES
+ help
+ There are certain POWER platforms which support secure guests using
+ the Protected Execution Facility, with the help of an Ultravisor
+ executing below the hypervisor layer. This enables support for
+ those guests.
+
+ If unsure, say "N".

2019-08-20 02:18:06

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [RFC PATCH v4 11/16] powerpc/pseries/svm: Export guest SVM status to user space via sysfs

From: Ryan Grimm <[email protected]>

User space might want to know it's running in a secure VM. It can't do
a mfmsr because mfmsr is a privileged instruction.

The solution here is to create a cpu attribute:

/sys/devices/system/cpu/svm

which will read 0 or 1 based on the S bit of the current CPU.

Signed-off-by: Ryan Grimm <[email protected]>
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
.../ABI/testing/sysfs-devices-system-cpu | 10 ++++++++++
arch/powerpc/kernel/sysfs.c | 20 +++++++++++++++++++
2 files changed, 30 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 5f7d7b14fa44..06d0931119cc 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -562,3 +562,13 @@ Description: Umwait control
or C0.2 state. The time is an unsigned 32-bit number.
Note that a value of zero means there is no limit.
Low order two bits must be zero.
+
+What: /sys/devices/system/cpu/svm
+Date: August 2019
+Contact: Linux kernel mailing list <[email protected]>
+ Linux for PowerPC mailing list <[email protected]>
+Description: Secure Virtual Machine
+
+ If 1, it means the system is using the Protected Execution
+ Facility in POWER9 and newer processors. i.e., it is a Secure
+ Virtual Machine.
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index e2147d7c9e72..80a676da11cb 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -19,6 +19,7 @@
#include <asm/smp.h>
#include <asm/pmc.h>
#include <asm/firmware.h>
+#include <asm/svm.h>

#include "cacheinfo.h"
#include "setup.h"
@@ -715,6 +716,23 @@ static struct device_attribute pa6t_attrs[] = {
#endif /* HAS_PPC_PMC_PA6T */
#endif /* HAS_PPC_PMC_CLASSIC */

+#ifdef CONFIG_PPC_SVM
+static ssize_t show_svm(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%u\n", is_secure_guest());
+}
+static DEVICE_ATTR(svm, 0444, show_svm, NULL);
+
+static void create_svm_file(void)
+{
+ device_create_file(cpu_subsys.dev_root, &dev_attr_svm);
+}
+#else
+static void create_svm_file(void)
+{
+}
+#endif /* CONFIG_PPC_SVM */
+
static int register_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
@@ -1058,6 +1076,8 @@ static int __init topology_init(void)
sysfs_create_dscr_default();
#endif /* CONFIG_PPC64 */

+ create_svm_file();
+
return 0;
}
subsys_initcall(topology_init);

2019-08-20 02:18:09

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 09/16] powerpc/pseries/svm: Use shared memory for Debug Trace Log (DTL)

From: Anshuman Khandual <[email protected]>

Secure guests need to share the DTL buffers with the hypervisor. To that
end, use a kmem_cache constructor which converts the underlying buddy
allocated SLUB cache pages into shared memory.

Signed-off-by: Anshuman Khandual <[email protected]>
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
arch/powerpc/include/asm/svm.h | 5 ++++
arch/powerpc/platforms/pseries/Makefile | 1 +
arch/powerpc/platforms/pseries/setup.c | 5 +++-
arch/powerpc/platforms/pseries/svm.c | 40 +++++++++++++++++++++++++
4 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/svm.h b/arch/powerpc/include/asm/svm.h
index 2689d8d841f8..85580b30aba4 100644
--- a/arch/powerpc/include/asm/svm.h
+++ b/arch/powerpc/include/asm/svm.h
@@ -15,6 +15,9 @@ static inline bool is_secure_guest(void)
return mfmsr() & MSR_S;
}

+void dtl_cache_ctor(void *addr);
+#define get_dtl_cache_ctor() (is_secure_guest() ? dtl_cache_ctor : NULL)
+
#else /* CONFIG_PPC_SVM */

static inline bool is_secure_guest(void)
@@ -22,5 +25,7 @@ static inline bool is_secure_guest(void)
return false;
}

+#define get_dtl_cache_ctor() NULL
+
#endif /* CONFIG_PPC_SVM */
#endif /* _ASM_POWERPC_SVM_H */
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index ab3d59aeacca..a420ef4c9d8e 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_IBMVIO) += vio.o
obj-$(CONFIG_IBMEBUS) += ibmebus.o
obj-$(CONFIG_PAPR_SCM) += papr_scm.o
obj-$(CONFIG_PPC_SPLPAR) += vphn.o
+obj-$(CONFIG_PPC_SVM) += svm.o

ifdef CONFIG_PPC_PSERIES
obj-$(CONFIG_SUSPEND) += suspend.o
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index f5940cc71c37..d8930c3a8a11 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -69,6 +69,7 @@
#include <asm/security_features.h>
#include <asm/asm-const.h>
#include <asm/swiotlb.h>
+#include <asm/svm.h>

#include "pseries.h"
#include "../../../../drivers/pci/pci.h"
@@ -297,8 +298,10 @@ static inline int alloc_dispatch_logs(void)

static int alloc_dispatch_log_kmem_cache(void)
{
+ void (*ctor)(void *) = get_dtl_cache_ctor();
+
dtl_cache = kmem_cache_create("dtl", DISPATCH_LOG_BYTES,
- DISPATCH_LOG_BYTES, 0, NULL);
+ DISPATCH_LOG_BYTES, 0, ctor);
if (!dtl_cache) {
pr_warn("Failed to create dispatch trace log buffer cache\n");
pr_warn("Stolen time statistics will be unreliable\n");
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
new file mode 100644
index 000000000000..2b2b1a77ca1e
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Secure VM platform
+ *
+ * Copyright 2018 IBM Corporation
+ * Author: Anshuman Khandual <[email protected]>
+ */
+
+#include <linux/mm.h>
+#include <asm/ultravisor.h>
+
+/* There's one dispatch log per CPU. */
+#define NR_DTL_PAGE (DISPATCH_LOG_BYTES * CONFIG_NR_CPUS / PAGE_SIZE)
+
+static struct page *dtl_page_store[NR_DTL_PAGE];
+static long dtl_nr_pages;
+
+static bool is_dtl_page_shared(struct page *page)
+{
+ long i;
+
+ for (i = 0; i < dtl_nr_pages; i++)
+ if (dtl_page_store[i] == page)
+ return true;
+
+ return false;
+}
+
+void dtl_cache_ctor(void *addr)
+{
+ unsigned long pfn = PHYS_PFN(__pa(addr));
+ struct page *page = pfn_to_page(pfn);
+
+ if (!is_dtl_page_shared(page)) {
+ dtl_page_store[dtl_nr_pages] = page;
+ dtl_nr_pages++;
+ WARN_ON(dtl_nr_pages >= NR_DTL_PAGE);
+ uv_share_page(pfn, 1);
+ }
+}

2019-08-20 02:18:26

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 12/16] powerpc/pseries/svm: Disable doorbells in SVM guests

From: Sukadev Bhattiprolu <[email protected]>

Normally, the HV emulates some instructions like MSGSNDP, MSGCLRP
from a KVM guest. To emulate the instructions, it must first read
the instruction from the guest's memory and decode its parameters.

However for a secure guest (aka SVM), the page containing the
instruction is in secure memory and the HV cannot access directly.
It would need the Ultravisor (UV) to facilitate accessing the
instruction and parameters but the UV currently does not have
the support for such accesses.

Until the UV has such support, disable doorbells in SVMs. This might
incur a performance hit but that is yet to be quantified.

With this patch applied (needed only in SVMs not needed for HV) we
are able to launch SVM guests with multi-core support. Eg:

qemu -smp sockets=2,cores=2,threads=2.

Fix suggested by Benjamin Herrenschmidt. Thanks to input from
Paul Mackerras, Ram Pai and Michael Anderson.

Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
arch/powerpc/platforms/pseries/smp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 4b3ef8d9c63f..ad61e90032da 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -41,6 +41,7 @@
#include <asm/dbell.h>
#include <asm/plpar_wrappers.h>
#include <asm/code-patching.h>
+#include <asm/svm.h>

#include "pseries.h"
#include "offline_states.h"
@@ -221,7 +222,7 @@ static __init void pSeries_smp_probe_xics(void)
{
xics_smp_probe();

- if (cpu_has_feature(CPU_FTR_DBELL))
+ if (cpu_has_feature(CPU_FTR_DBELL) && !is_secure_guest())
smp_ops->cause_ipi = smp_pseries_cause_ipi;
else
smp_ops->cause_ipi = icp_ops->cause_ipi;

2019-08-20 02:18:54

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 16/16] powerpc/configs: Enable secure guest support in pseries and ppc64 defconfigs

From: Ryan Grimm <[email protected]>

Enables running as a secure guest in platforms with an Ultravisor.

Signed-off-by: Ryan Grimm <[email protected]>
Signed-off-by: Ram Pai <[email protected]>
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
arch/powerpc/configs/ppc64_defconfig | 1 +
arch/powerpc/configs/pseries_defconfig | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig
index dc83fefa04f7..b250e6f5a7ca 100644
--- a/arch/powerpc/configs/ppc64_defconfig
+++ b/arch/powerpc/configs/ppc64_defconfig
@@ -29,6 +29,7 @@ CONFIG_DTL=y
CONFIG_SCANLOG=m
CONFIG_PPC_SMLPAR=y
CONFIG_IBMEBUS=y
+CONFIG_PPC_SVM=y
CONFIG_PPC_MAPLE=y
CONFIG_PPC_PASEMI=y
CONFIG_PPC_PASEMI_IOMMU=y
diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig
index 38abc9c1770a..26126b4d4de3 100644
--- a/arch/powerpc/configs/pseries_defconfig
+++ b/arch/powerpc/configs/pseries_defconfig
@@ -42,6 +42,7 @@ CONFIG_DTL=y
CONFIG_SCANLOG=m
CONFIG_PPC_SMLPAR=y
CONFIG_IBMEBUS=y
+CONFIG_PPC_SVM=y
# CONFIG_PPC_PMAC is not set
CONFIG_RTAS_FLASH=m
CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y

2019-08-20 02:19:29

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 13/16] powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests

Secure guest memory is inacessible to devices so regular DMA isn't
possible.

In that case set devices' dma_map_ops to NULL so that the generic
DMA code path will use SWIOTLB to bounce buffers for DMA.

Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
arch/powerpc/platforms/pseries/iommu.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 889dc2e44b89..8d9c2b17ad54 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -36,6 +36,7 @@
#include <asm/udbg.h>
#include <asm/mmzone.h>
#include <asm/plpar_wrappers.h>
+#include <asm/svm.h>

#include "pseries.h"

@@ -1318,7 +1319,15 @@ void iommu_init_early_pSeries(void)
of_reconfig_notifier_register(&iommu_reconfig_nb);
register_memory_notifier(&iommu_mem_nb);

- set_pci_dma_ops(&dma_iommu_ops);
+ /*
+ * Secure guest memory is inacessible to devices so regular DMA isn't
+ * possible.
+ *
+ * In that case keep devices' dma_map_ops as NULL so that the generic
+ * DMA code path will use SWIOTLB to bounce buffers for DMA.
+ */
+ if (!is_secure_guest())
+ set_pci_dma_ops(&dma_iommu_ops);
}

static int __init disable_multitce(char *str)

2019-08-20 02:19:52

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 14/16] powerpc/pseries/svm: Force SWIOTLB for secure guests

From: Anshuman Khandual <[email protected]>

SWIOTLB checks range of incoming CPU addresses to be bounced and sees if
the device can access it through its DMA window without requiring bouncing.
In such cases it just chooses to skip bouncing. But for cases like secure
guests on powerpc platform all addresses need to be bounced into the shared
pool of memory because the host cannot access it otherwise. Hence the need
to do the bouncing is not related to device's DMA window and use of bounce
buffers is forced by setting swiotlb_force.

Also, connect the shared memory conversion functions into the
ARCH_HAS_MEM_ENCRYPT hooks and call swiotlb_update_mem_attributes() to
convert SWIOTLB's memory pool to shared memory.

Signed-off-by: Anshuman Khandual <[email protected]>
[ bauerman: Use ARCH_HAS_MEM_ENCRYPT hooks to share swiotlb memory pool. ]
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
arch/powerpc/include/asm/mem_encrypt.h | 26 +++++++++++++++
arch/powerpc/platforms/pseries/Kconfig | 3 ++
arch/powerpc/platforms/pseries/svm.c | 45 ++++++++++++++++++++++++++
3 files changed, 74 insertions(+)

diff --git a/arch/powerpc/include/asm/mem_encrypt.h b/arch/powerpc/include/asm/mem_encrypt.h
new file mode 100644
index 000000000000..ba9dab07c1be
--- /dev/null
+++ b/arch/powerpc/include/asm/mem_encrypt.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * SVM helper functions
+ *
+ * Copyright 2018 IBM Corporation
+ */
+
+#ifndef _ASM_POWERPC_MEM_ENCRYPT_H
+#define _ASM_POWERPC_MEM_ENCRYPT_H
+
+#include <asm/svm.h>
+
+static inline bool mem_encrypt_active(void)
+{
+ return is_secure_guest();
+}
+
+static inline bool force_dma_unencrypted(struct device *dev)
+{
+ return is_secure_guest();
+}
+
+int set_memory_encrypted(unsigned long addr, int numpages);
+int set_memory_decrypted(unsigned long addr, int numpages);
+
+#endif /* _ASM_POWERPC_MEM_ENCRYPT_H */
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index d09deb05bb66..9e35cddddf73 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -149,6 +149,9 @@ config PAPR_SCM
config PPC_SVM
bool "Secure virtual machine (SVM) support for POWER"
depends on PPC_PSERIES
+ select SWIOTLB
+ select ARCH_HAS_MEM_ENCRYPT
+ select ARCH_HAS_FORCE_DMA_UNENCRYPTED
help
There are certain POWER platforms which support secure guests using
the Protected Execution Facility, with the help of an Ultravisor
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index 2b2b1a77ca1e..40c0637203d5 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -7,8 +7,53 @@
*/

#include <linux/mm.h>
+#include <asm/machdep.h>
+#include <asm/svm.h>
+#include <asm/swiotlb.h>
#include <asm/ultravisor.h>

+static int __init init_svm(void)
+{
+ if (!is_secure_guest())
+ return 0;
+
+ /* Don't release the SWIOTLB buffer. */
+ ppc_swiotlb_enable = 1;
+
+ /*
+ * Since the guest memory is inaccessible to the host, devices always
+ * need to use the SWIOTLB buffer for DMA even if dma_capable() says
+ * otherwise.
+ */
+ swiotlb_force = SWIOTLB_FORCE;
+
+ /* Share the SWIOTLB buffer with the host. */
+ swiotlb_update_mem_attributes();
+
+ return 0;
+}
+machine_early_initcall(pseries, init_svm);
+
+int set_memory_encrypted(unsigned long addr, int numpages)
+{
+ if (!PAGE_ALIGNED(addr))
+ return -EINVAL;
+
+ uv_unshare_page(PHYS_PFN(__pa(addr)), numpages);
+
+ return 0;
+}
+
+int set_memory_decrypted(unsigned long addr, int numpages)
+{
+ if (!PAGE_ALIGNED(addr))
+ return -EINVAL;
+
+ uv_share_page(PHYS_PFN(__pa(addr)), numpages);
+
+ return 0;
+}
+
/* There's one dispatch log per CPU. */
#define NR_DTL_PAGE (DISPATCH_LOG_BYTES * CONFIG_NR_CPUS / PAGE_SIZE)

2019-08-20 02:19:55

by Thiago Jung Bauermann

[permalink] [raw]
Subject: [PATCH v4 15/16] Documentation/powerpc: Ultravisor API

From: Sukadev Bhattiprolu <[email protected]>

POWER9 processor includes support for Protected Execution Facility (PEF).
Attached documentation provides an overview of PEF and defines the API
for various interfaces that must be implemented in the Ultravisor
firmware as well as in the KVM Hypervisor.

Based on input from Mike Anderson, Thiago Bauermann, Claudio Carvalho,
Ben Herrenschmidt, Guerney Hunt, Paul Mackerras.

Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Signed-off-by: Ram Pai <[email protected]>
Signed-off-by: Guerney Hunt <[email protected]>
Reviewed-by: Claudio Carvalho <[email protected]>
Reviewed-by: Michael Anderson <[email protected]>
Reviewed-by: Thiago Bauermann <[email protected]>
Signed-off-by: Claudio Carvalho <[email protected]>
Signed-off-by: Thiago Jung Bauermann <[email protected]>
---
Documentation/powerpc/ultravisor.rst | 1055 ++++++++++++++++++++++++++
1 file changed, 1055 insertions(+)

diff --git a/Documentation/powerpc/ultravisor.rst b/Documentation/powerpc/ultravisor.rst
new file mode 100644
index 000000000000..8d5246585b66
--- /dev/null
+++ b/Documentation/powerpc/ultravisor.rst
@@ -0,0 +1,1055 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. _ultravisor:
+
+============================
+Protected Execution Facility
+============================
+
+.. contents::
+ :depth: 3
+
+.. sectnum::
+ :depth: 3
+
+Protected Execution Facility
+############################
+
+ Protected Execution Facility (PEF) is an architectural change for
+ POWER 9 that enables Secure Virtual Machines (SVMs). When enabled,
+ PEF adds a new higher privileged mode, called Ultravisor mode, to
+ POWER architecture. Along with the new mode there is new firmware
+ called the Protected Execution Ultravisor (or Ultravisor for short).
+ Ultravisor mode is the highest privileged mode in POWER architecture.
+
+ +------------------+
+ | Privilege States |
+ +==================+
+ | Problem |
+ +------------------+
+ | Supervisor |
+ +------------------+
+ | Hypervisor |
+ +------------------+
+ | Ultravisor |
+ +------------------+
+
+ PEF protects SVMs from the hypervisor, privileged users, and other
+ VMs in the system. SVMs are protected while at rest and can only be
+ executed by an authorized machine. All virtual machines utilize
+ hypervisor services. The Ultravisor filters calls between the SVMs
+ and the hypervisor to assure that information does not accidentally
+ leak. All hypercalls except H_RANDOM are reflected to the hypervisor.
+ H_RANDOM is not reflected to prevent the hypervisor from influencing
+ random values in the SVM.
+
+ To support this there is a refactoring of the ownership of resources
+ in the CPU. Some of the resources which were previously hypervisor
+ privileged are now ultravisor privileged.
+
+Hardware
+========
+
+ The hardware changes include the following:
+
+ * There is a new bit in the MSR that determines whether the current
+ process is running in secure mode, MSR(S) bit 41. MSR(S)=1, process
+ is in secure mode, MSR(s)=0 process is in normal mode.
+
+ * The MSR(S) bit can only be set by the Ultravisor.
+
+ * HRFID cannot be used to set the MSR(S) bit. If the hypervisor needs
+ to return to a SVM it must use an ultracall. It can determine if
+ the VM it is returning to is secure.
+
+ * There is a new Ultravisor privileged register, SMFCTRL, which has an
+ enable/disable bit SMFCTRL(E).
+
+ * The privilege of a process is now determined by three MSR bits,
+ MSR(S, HV, PR). In each of the tables below the modes are listed
+ from least privilege to highest privilege. The higher privilege
+ modes can access all the resources of the lower privilege modes.
+
+ **Secure Mode MSR Settings**
+
+ +---+---+---+---------------+
+ | S | HV| PR|Privilege |
+ +===+===+===+===============+
+ | 1 | 0 | 1 | Problem |
+ +---+---+---+---------------+
+ | 1 | 0 | 0 | Privileged(OS)|
+ +---+---+---+---------------+
+ | 1 | 1 | 0 | Ultravisor |
+ +---+---+---+---------------+
+ | 1 | 1 | 1 | Reserved |
+ +---+---+---+---------------+
+
+ **Normal Mode MSR Settings**
+
+ +---+---+---+---------------+
+ | S | HV| PR|Privilege |
+ +===+===+===+===============+
+ | 0 | 0 | 1 | Problem |
+ +---+---+---+---------------+
+ | 0 | 0 | 0 | Privileged(OS)|
+ +---+---+---+---------------+
+ | 0 | 1 | 0 | Hypervisor |
+ +---+---+---+---------------+
+ | 0 | 1 | 1 | Problem (HV) |
+ +---+---+---+---------------+
+
+ * Memory is partitioned into secure and normal memory. Only processes
+ that are running in secure mode can access secure memory.
+
+ * The hardware does not allow anything that is not running secure to
+ access secure memory. This means that the Hypervisor cannot access
+ the memory of the SVM without using an ultracall (asking the
+ Ultravisor). The Ultravisor will only allow the hypervisor to see
+ the SVM memory encrypted.
+
+ * I/O systems are not allowed to directly address secure memory. This
+ limits the SVMs to virtual I/O only.
+
+ * The architecture allows the SVM to share pages of memory with the
+ hypervisor that are not protected with encryption. However, this
+ sharing must be initiated by the SVM.
+
+ * When a process is running in secure mode all hypercalls
+ (syscall lev=1) are reflected to the Ultravisor.
+
+ * When a process is in secure mode all interrupts go to the
+ Ultravisor.
+
+ * The following resources have become Ultravisor privileged and
+ require an Ultravisor interface to manipulate:
+
+ * Processor configurations registers (SCOMs).
+
+ * Stop state information.
+
+ * The debug registers CIABR, DAWR, and DAWRX become Ultravisor
+ resources when SMFCTRL(D) is set. If SMFCTRL(D) is not set they do
+ not work in secure mode. When set, reading and writing requires
+ an Ultravisor call, otherwise that will cause a Hypervisor Emulation
+ Assistance interrupt.
+
+ * PTCR and partition table entries (partition table is in secure
+ memory). An attempt to write to PTCR will cause a Hypervisor
+ Emulation Assitance interrupt.
+
+ * LDBAR (LD Base Address Register) and IMC (In-Memory Collection)
+ non-architected registers. An attempt to write to them will cause a
+ Hypervisor Emulation Assistance interrupt.
+
+ * Paging for an SVM, sharing of memory with Hypervisor for an SVM.
+ (Including Virtual Processor Area (VPA) and virtual I/O).
+
+
+Software/Microcode
+==================
+
+ The software changes include:
+
+ * SVMs are created from normal VM using (open source) tooling supplied
+ by IBM.
+
+ * All SVMs start as normal VMs and utilize an ultracall, UV_ESM
+ (Enter Secure Mode), to make the transition.
+
+ * When the UV_ESM ultracall is made the Ultravisor copies the VM into
+ secure memory, decrypts the verification information, and checks the
+ integrity of the SVM. If the integrity check passes the Ultravisor
+ passes control in secure mode.
+
+ * For external interrupts the Ultravisor saves the state of the SVM,
+ and reflects the interrupt to the hypervisor for processing.
+ For hypercalls, the Ultravisor inserts neutral state into all
+ registers not needed for the hypercall then reflects the call to
+ the hypervisor for processing. The H_RANDOM hypercall is performed
+ by the Ultravisor and not reflected.
+
+ * The verification information includes the pass phrase for the
+ encrypted disk associated with the SVM. This pass phrase is given
+ to the SVM when requested.
+
+ * The Ultravisor is not involved in protecting the encrypted disk of
+ the SVM while at rest.
+
+ * For virtual I/O to work bounce buffering must be done.
+
+ * The Ultravisor uses AES (IAPM) for protection of SVM memory. IAPM
+ is a mode of AES that provides integrity and secrecy concurrently.
+
+ * The movement of data between normal and secure pages is coordinated
+ with the Ultravisor by a new HMM plug-in in the Hypervisor.
+
+ The Ultravisor offers new services to the hypervisor and SVMs. These
+ are accessed through ultracalls.
+
+Terminology
+===========
+
+ * Hypercalls: special system calls used to request services from
+ Hypervisor.
+
+ * Normal memory: Memory that is accessible to Hypervisor.
+
+ * Normal page: Page backed by normal memory and available to
+ Hypervisor.
+
+ * Shared page: A page backed by normal memory and available to both
+ the Hypervisor/QEMU and the SVM (i.e page has mappings in SVM and
+ Hypervisor/QEMU).
+
+ * Secure memory: Memory that is accessible only to Ultravisor and
+ SVMs.
+
+ * Secure page: Page backed by secure memory and only available to
+ Ultravisor and SVM.
+
+ * SVM: Secure Virtual Machine.
+
+ * Ultracalls: special system calls used to request services from
+ Ultravisor.
+
+
+Ultravisor calls API
+####################
+
+ This section describes Ultravisor calls (ultracalls) needed to
+ support Secure Virtual Machines (SVM)s and Paravirtalized KVM. The
+ ultracalls allow the SVMs and Hypervisor to request services from the
+ Ultravisor such as accessing a register or memory region that can only
+ be accessed when running in Ultravisor-privileged mode.
+
+ The specific service needed from an ultracall is specified in register
+ R3 (the first parameter to the ultracall). Other parameters to the
+ ultracall, if any, are specified in registers R4 through R12.
+
+ Return value of all ultracalls is in register R3. Other output values
+ from the ultracall, if any, are returned in registers R4 through R12.
+ The only exception to this register usage is the ``UV_RETURN``
+ ultracall described below.
+
+ Each ultracall returns specific error codes, applicable in the context
+ of the ultracall. However, like with the PowerPC Architecture Platform
+ Reference (PAPR), if no specific error code is defined for a
+ particular situation, then the ultracall will fallback to an erroneous
+ parameter-position based code. i.e U_PARAMETER, U_P2, U_P3 etc
+ depending on the ultracall parameter that may have caused the error.
+
+ Some ultracalls involve transferring a page of data between Ultravisor
+ and Hypervisor. Secure pages that are transferred from secure memory
+ to normal memory may be encrypted using dynamically generated keys.
+ When the secure pages are transferred back to secure memory, they may
+ be decrypted using the same dynamically generated keys. Generation and
+ management of these keys will be covered in a separate document.
+
+ For now this only covers ultracalls currently implemented and being
+ used by Hypervisor and SVMs but others can be added here when it
+ makes sense.
+
+ The full specification for all hypercalls/ultracalls will eventually
+ be made available in the public/OpenPower version of the PAPR
+ specification.
+
+ **Note**
+
+ If PEF is not enabled, the ultracalls will be redirected to the
+ Hypervisor which must handle/fail the calls.
+
+Ultracalls used by Hypervisor
+=============================
+
+ This section describes the virtual memory management ultracalls used
+ by the Hypervisor to manage SVMs.
+
+UV_PAGE_OUT
+-----------
+
+ Encrypt and move the contents of a page from secure memory to normal
+ memory.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_PAGE_OUT,
+ uint16_t lpid, /* LPAR ID */
+ uint64_t dest_ra, /* real address of destination page */
+ uint64_t src_gpa, /* source guest-physical-address */
+ uint8_t flags, /* flags */
+ uint64_t order) /* page size order */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_PARAMETER if ``lpid`` is invalid.
+ * U_P2 if ``dest_ra`` is invalid.
+ * U_P3 if the ``src_gpa`` address is invalid.
+ * U_P4 if any bit in the ``flags`` is unrecognized
+ * U_P5 if the ``order`` parameter is unsupported.
+ * U_FUNCTION if functionality is not supported.
+ * U_BUSY if page cannot be currently paged-out.
+
+Description
+~~~~~~~~~~~
+
+ Encrypt the contents of a secure-page and make it available to
+ Hypervisor in a normal page.
+
+ By default, the source page is unmapped from the SVM's partition-
+ scoped page table. But the Hypervisor can provide a hint to the
+ Ultravisor to retain the page mapping by setting the ``UV_SNAPSHOT``
+ flag in ``flags`` parameter.
+
+ If the source page is already a shared page the call returns
+ U_SUCCESS, without doing anything.
+
+Use cases
+~~~~~~~~~
+
+ #. QEMU attempts to access an address belonging to the SVM but the
+ page frame for that address is not mapped into QEMU's address
+ space. In this case, the Hypervisor will allocate a page frame,
+ map it into QEMU's address space and issue the ``UV_PAGE_OUT``
+ call to retrieve the encrypted contents of the page.
+
+ #. When Ultravisor runs low on secure memory and it needs to page-out
+ an LRU page. In this case, Ultravisor will issue the
+ ``H_SVM_PAGE_OUT`` hypercall to the Hypervisor. The Hypervisor will
+ then allocate a normal page and issue the ``UV_PAGE_OUT`` ultracall
+ and the Ultravisor will encrypt and move the contents of the secure
+ page into the normal page.
+
+
+UV_PAGE_IN
+----------
+
+ Move the contents of a page from normal memory to secure memory.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_PAGE_IN,
+ uint16_t lpid, /* the LPAR ID */
+ uint64_t src_ra, /* source real address of page */
+ uint64_t dest_gpa, /* destination guest physical address */
+ uint64_t flags, /* flags */
+ uint64_t order) /* page size order */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_BUSY if page cannot be currently paged-in.
+ * U_FUNCTION if functionality is not supported
+ * U_PARAMETER if ``lpid`` is invalid.
+ * U_P2 if ``src_ra`` is invalid.
+ * U_P3 if the ``dest_gpa`` address is invalid.
+ * U_P4 if any bit in the ``flags`` is unrecognized
+ * U_P5 if the ``order`` parameter is unsupported.
+
+Description
+~~~~~~~~~~~
+
+ Move the contents of the page identified by ``src_ra`` from normal
+ memory to secure memory and map it to the guest physical address
+ ``dest_gpa``.
+
+ If `dest_gpa` refers to a shared address, map the page into the
+ partition-scoped page-table of the SVM. If `dest_gpa` is not shared,
+ copy the contents of the page into the corresponding secure page.
+ Depending on the context, decrypt the page before being copied.
+
+ The caller provides the attributes of the page through the ``flags``
+ parameter. Valid values for ``flags`` are:
+
+ * CACHE_INHIBITED
+ * CACHE_ENABLED
+ * WRITE_PROTECTION
+
+ The Hypervisor must pin the page in memory before making
+ ``UV_PAGE_IN`` ultracall.
+
+Use cases
+~~~~~~~~~
+
+ #. When a normal VM switches to secure mode, all its pages residing
+ in normal memory, are moved into secure memory.
+
+ #. When an SVM requests to share a page with Hypervisor the Hypervisor
+ allocates a page and informs the Ultravisor.
+
+ #. When an SVM accesses a secure page that has been paged-out,
+ Ultravisor invokes the Hypervisor to locate the page. After
+ locating the page, the Hypervisor uses UV_PAGE_IN to make the
+ page available to Ultravisor.
+
+ #. When Hypervisor accesses SVM data, the Hypervisor requests the
+ Ultravisor to transfer the corresponding page into a insecure page,
+ which the Hypervisor can access. The data in the normal page will
+ be encrypted though.
+
+UV_PAGE_INVAL
+-------------
+
+ Invalidate the Ultravisor mapping of a page.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_PAGE_INVAL,
+ uint16_t lpid, /* the LPAR ID */
+ uint64_t guest_pa, /* destination guest-physical-address */
+ uint64_t order) /* page size order */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_PARAMETER if ``lpid`` is invalid.
+ * U_P2 if ``guest_pa`` is invalid (or corresponds to a secure
+ page mapping).
+ * U_P3 if the ``order`` is invalid.
+ * U_FUNCTION if functionality is not supported.
+ * U_BUSY if page cannot be currently invalidated.
+
+Description
+~~~~~~~~~~~
+
+ This ultracall informs Ultravisor that the page mapping in Hypervisor
+ corresponding to the given guest physical address has been invalidated
+ and that the Ultravisor should not access the page. If the specified
+ ``guest_pa`` corresponds to a secure page, Ultravisor will ignore the
+ attempt to invalidate the page and return U_P2.
+
+Use cases
+~~~~~~~~~
+
+ #. When a shared page is unmapped from the QEMU's page table, possibly
+ because it is paged-out to disk, Ultravisor needs to know that the
+ page should not be accessed from its side too.
+
+
+UV_WRITE_PATE
+-------------
+
+ Validate and write the partition table entry (PATE) for a given
+ partition.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_WRITE_PATE,
+ uint32_t lpid, /* the LPAR ID */
+ uint64_t dw0 /* the first double word to write */
+ uint64_t dw1) /* the second double word to write */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_BUSY if PATE cannot be currently written to.
+ * U_FUNCTION if functionality is not supported.
+ * U_PARAMETER if ``lpid`` is invalid.
+ * U_P2 if ``dw0`` is invalid.
+ * U_P3 if the ``dw1`` address is invalid.
+ * U_PERMISSION if the Hypervisor is attempting to change the PATE
+ of a secure virtual machine or if called from a
+ context other than Hypervisor.
+
+Description
+~~~~~~~~~~~
+
+ Validate and write a LPID and its partition-table-entry for the given
+ LPID. If the LPID is already allocated and initialized, this call
+ results in changing the partition table entry.
+
+Use cases
+~~~~~~~~~
+
+ #. The Partition table resides in Secure memory and its entries,
+ called PATE (Partition Table Entries), point to the partition-
+ scoped page tables for the Hypervisor as well as each of the
+ virtual machines (both secure and normal). The Hypervisor
+ operates in partition 0 and its partition-scoped page tables
+ reside in normal memory.
+
+ #. This ultracall allows the Hypervisor to register the partition-
+ scoped and process-scoped page table entries for the Hypervisor
+ and other partitions (virtual machines) with the Ultravisor.
+
+ #. If the value of the PATE for an existing partition (VM) changes,
+ the TLB cache for the partition is flushed.
+
+ #. The Hypervisor is responsible for allocating LPID. The LPID and
+ its PATE entry are registered together. The Hypervisor manages
+ the PATE entries for a normal VM and can change the PATE entry
+ anytime. Ultravisor manages the PATE entries for an SVM and
+ Hypervisor is not allowed to modify them.
+
+UV_RETURN
+---------
+
+ Return control from the Hypervisor back to the Ultravisor after
+ processing an hypercall or interrupt that was forwarded (aka
+ *reflected*) to the Hypervisor.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_RETURN)
+
+Return values
+~~~~~~~~~~~~~
+
+ This call never returns to Hypervisor on success. It returns
+ U_INVALID if ultracall is not made from a Hypervisor context.
+
+Description
+~~~~~~~~~~~
+
+ When an SVM makes an hypercall or incurs some other exception, the
+ Ultravisor usually forwards (aka *reflects*) the exceptions to the
+ Hypervisor. After processing the exception, Hypervisor uses the
+ ``UV_RETURN`` ultracall to return control back to the SVM.
+
+ The expected register state on entry to this ultracall is:
+
+ * Non-volatile registers are restored to their original values.
+ * If returning from an hypercall, register R0 contains the return
+ value (**unlike other ultracalls**) and, registers R4 through R12
+ contain any output values of the hypercall.
+ * R3 contains the ultracall number, i.e UV_RETURN.
+ * If returning with a synthesized interrupt, R2 contains the
+ synthesized interrupt number.
+
+Use cases
+~~~~~~~~~
+
+ #. Ultravisor relies on the Hypervisor to provide several services to
+ the SVM such as processing hypercall and other exceptions. After
+ processing the exception, Hypervisor uses UV_RETURN to return
+ control back to the Ultravisor.
+
+ #. Hypervisor has to use this ultracall to return control to the SVM.
+
+
+UV_REGISTER_MEM_SLOT
+--------------------
+
+ Register an SVM address-range with specified properties.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_REGISTER_MEM_SLOT,
+ uint64_t lpid, /* LPAR ID of the SVM */
+ uint64_t start_gpa, /* start guest physical address */
+ uint64_t size, /* size of address range in bytes */
+ uint64_t flags /* reserved for future expansion */
+ uint16_t slotid) /* slot identifier */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_PARAMETER if ``lpid`` is invalid.
+ * U_P2 if ``start_gpa`` is invalid.
+ * U_P3 if ``size`` is invalid.
+ * U_P4 if any bit in the ``flags`` is unrecognized.
+ * U_P5 if the ``slotid`` parameter is unsupported.
+ * U_PERMISSION if called from context other than Hypervisor.
+ * U_FUNCTION if functionality is not supported.
+
+
+Description
+~~~~~~~~~~~
+
+ Register a memory range for an SVM. The memory range starts at the
+ guest physical address ``start_gpa`` and is ``size`` bytes long.
+
+Use cases
+~~~~~~~~~
+
+
+ #. When a virtual machine goes secure, all the memory slots managed by
+ the Hypervisor move into secure memory. The Hypervisor iterates
+ through each of memory slots, and registers the slot with
+ Ultravisor. Hypervisor may discard some slots such as those used
+ for firmware (SLOF).
+
+ #. When new memory is hot-plugged, a new memory slot gets registered.
+
+
+UV_UNREGISTER_MEM_SLOT
+----------------------
+
+ Unregister an SVM address-range that was previously registered using
+ UV_REGISTER_MEM_SLOT.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_UNREGISTER_MEM_SLOT,
+ uint64_t lpid, /* LPAR ID of the SVM */
+ uint64_t slotid) /* reservation slotid */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_FUNCTION if functionality is not supported.
+ * U_PARAMETER if ``lpid`` is invalid.
+ * U_P2 if ``slotid`` is invalid.
+ * U_PERMISSION if called from context other than Hypervisor.
+
+Description
+~~~~~~~~~~~
+
+ Release the memory slot identified by ``slotid`` and free any
+ resources allocated towards the reservation.
+
+Use cases
+~~~~~~~~~
+
+ #. Memory hot-remove.
+
+
+UV_SVM_TERMINATE
+----------------
+
+ Terminate an SVM and release its resources.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_SVM_TERMINATE,
+ uint64_t lpid, /* LPAR ID of the SVM */)
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_FUNCTION if functionality is not supported.
+ * U_PARAMETER if ``lpid`` is invalid.
+ * U_INVALID if VM is not secure.
+ * U_PERMISSION if not called from a Hypervisor context.
+
+Description
+~~~~~~~~~~~
+
+ Terminate an SVM and release all its resources.
+
+Use cases
+~~~~~~~~~
+
+ #. Called by Hypervisor when terminating an SVM.
+
+
+Ultracalls used by SVM
+======================
+
+UV_SHARE_PAGE
+-------------
+
+ Share a set of guest physical pages with the Hypervisor.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_SHARE_PAGE,
+ uint64_t gfn, /* guest page frame number */
+ uint64_t num) /* number of pages of size PAGE_SIZE */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_FUNCTION if functionality is not supported.
+ * U_INVALID if the VM is not secure.
+ * U_PARAMETER if ``gfn`` is invalid.
+ * U_P2 if ``num`` is invalid.
+
+Description
+~~~~~~~~~~~
+
+ Share the ``num`` pages starting at guest physical frame number ``gfn``
+ with the Hypervisor. Assume page size is PAGE_SIZE bytes. Zero the
+ pages before returning.
+
+ If the address is already backed by a secure page, unmap the page and
+ back it with an insecure page, with the help of the Hypervisor. If it
+ is not backed by any page yet, mark the PTE as insecure and back it
+ with an insecure page when the address is accessed. If it is already
+ backed by an insecure page, zero the page and return.
+
+Use cases
+~~~~~~~~~
+
+ #. The Hypervisor cannot access the SVM pages since they are backed by
+ secure pages. Hence an SVM must explicitly request Ultravisor for
+ pages it can share with Hypervisor.
+
+ #. Shared pages are needed to support virtio and Virtual Processor Area
+ (VPA) in SVMs.
+
+
+UV_UNSHARE_PAGE
+---------------
+
+ Restore a shared SVM page to its initial state.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_UNSHARE_PAGE,
+ uint64_t gfn, /* guest page frame number */
+ uint73 num) /* number of pages of size PAGE_SIZE*/
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_FUNCTION if functionality is not supported.
+ * U_INVALID if VM is not secure.
+ * U_PARAMETER if ``gfn`` is invalid.
+ * U_P2 if ``num`` is invalid.
+
+Description
+~~~~~~~~~~~
+
+ Stop sharing ``num`` pages starting at ``gfn`` with the Hypervisor.
+ Assume that the page size is PAGE_SIZE. Zero the pages before
+ returning.
+
+ If the address is already backed by an insecure page, unmap the page
+ and back it with a secure page. Inform the Hypervisor to release
+ reference to its shared page. If the address is not backed by a page
+ yet, mark the PTE as secure and back it with a secure page when that
+ address is accessed. If it is already backed by an secure page zero
+ the page and return.
+
+Use cases
+~~~~~~~~~
+
+ #. The SVM may decide to unshare a page from the Hypervisor.
+
+
+UV_UNSHARE_ALL_PAGES
+--------------------
+
+ Unshare all pages the SVM has shared with Hypervisor.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_UNSHARE_ALL_PAGES)
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success.
+ * U_FUNCTION if functionality is not supported.
+ * U_INVAL if VM is not secure.
+
+Description
+~~~~~~~~~~~
+
+ Unshare all shared pages from the Hypervisor. All unshared pages are
+ zeroed on return. Only pages explicitly shared by the SVM with the
+ Hypervisor (using UV_SHARE_PAGE ultracall) are unshared. Ultravisor
+ may internally share some pages with the Hypervisor without explicit
+ request from the SVM. These pages will not be unshared by this
+ ultracall.
+
+Use cases
+~~~~~~~~~
+
+ #. This call is needed when ``kexec`` is used to boot a different
+ kernel. It may also be needed during SVM reset.
+
+UV_ESM
+------
+
+ Secure the virtual machine (*enter secure mode*).
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t ultracall(const uint64_t UV_ESM,
+ uint64_t esm_blob_addr, /* location of the ESM blob */
+ unint64_t fdt) /* Flattened device tree */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * U_SUCCESS on success (including if VM is already secure).
+ * U_FUNCTION if functionality is not supported.
+ * U_INVALID if VM is not secure.
+ * U_PARAMETER if ``esm_blob_addr`` is invalid.
+ * U_P2 if ``fdt`` is invalid.
+ * U_PERMISSION if any integrity checks fail.
+ * U_RETRY insufficient memory to create SVM.
+ * U_NO_KEY symmetric key unavailable.
+
+Description
+~~~~~~~~~~~
+
+ Secure the virtual machine. On successful completion, return
+ control to the virtual machine at the address specified in the
+ ESM blob.
+
+Use cases
+~~~~~~~~~
+
+ #. A normal virtual machine can choose to switch to a secure mode.
+
+Hypervisor Calls API
+####################
+
+ This document describes the Hypervisor calls (hypercalls) that are
+ needed to support the Ultravisor. Hypercalls are services provided by
+ the Hypervisor to virtual machines and Ultravisor.
+
+ Register usage for these hypercalls is identical to that of the other
+ hypercalls defined in the Power Architecture Platform Reference (PAPR)
+ document. i.e on input, register R3 identifies the specific service
+ that is being requested and registers R4 through R11 contain
+ additional parameters to the hypercall, if any. On output, register
+ R3 contains the return value and registers R4 through R9 contain any
+ other output values from the hypercall.
+
+ This document only covers hypercalls currently implemented/planned
+ for Ultravisor usage but others can be added here when it makes sense.
+
+ The full specification for all hypercalls/ultracalls will eventually
+ be made available in the public/OpenPower version of the PAPR
+ specification.
+
+Hypervisor calls to support Ultravisor
+======================================
+
+ Following are the set of hypercalls needed to support Ultravisor.
+
+H_SVM_INIT_START
+----------------
+
+ Begin the process of converting a normal virtual machine into an SVM.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t hypercall(const uint64_t H_SVM_INIT_START)
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * H_SUCCESS on success.
+
+Description
+~~~~~~~~~~~
+
+ Initiate the process of securing a virtual machine. This involves
+ coordinating with the Ultravisor, using ultracalls, to allocate
+ resources in the Ultravisor for the new SVM, transferring the VM's
+ pages from normal to secure memory etc. When the process is
+ completed, Ultravisor issues the H_SVM_INIT_DONE hypercall.
+
+Use cases
+~~~~~~~~~
+
+ #. Ultravisor uses this hypercall to inform Hypervisor that a VM
+ has initiated the process of switching to secure mode.
+
+
+H_SVM_INIT_DONE
+---------------
+
+ Complete the process of securing an SVM.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t hypercall(const uint64_t H_SVM_INIT_DONE)
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * H_SUCCESS on success.
+ * H_UNSUPPORTED if called from the wrong context (e.g.
+ from an SVM or before an H_SVM_INIT_START
+ hypercall).
+
+Description
+~~~~~~~~~~~
+
+ Complete the process of securing a virtual machine. This call must
+ be made after a prior call to ``H_SVM_INIT_START`` hypercall.
+
+Use cases
+~~~~~~~~~
+
+ On successfully securing a virtual machine, the Ultravisor informs
+ Hypervisor about it. Hypervisor can use this call to finish setting
+ up its internal state for this virtual machine.
+
+
+H_SVM_PAGE_IN
+-------------
+
+ Move the contents of a page from normal memory to secure memory.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t hypercall(const uint64_t H_SVM_PAGE_IN,
+ uint64_t guest_pa, /* guest-physical-address */
+ uint64_t flags, /* flags */
+ uint64_t order) /* page size order */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * H_SUCCESS on success.
+ * H_PARAMETER if ``guest_pa`` is invalid.
+ * H_P2 if ``flags`` is invalid.
+ * H_P3 if ``order`` of page is invalid.
+
+Description
+~~~~~~~~~~~
+
+ Retrieve the content of the page, belonging to the VM at the specified
+ guest physical address.
+
+ Only valid value(s) in ``flags`` are:
+
+ * H_PAGE_IN_SHARED which indicates that the page is to be shared
+ with the Ultravisor.
+
+ * H_PAGE_IN_NONSHARED indicates that the UV is not anymore
+ interested in the page. Applicable if the page is a shared page.
+
+ The ``order`` parameter must correspond to the configured page size.
+
+Use cases
+~~~~~~~~~
+
+ #. When a normal VM becomes a secure VM (using the UV_ESM ultracall),
+ the Ultravisor uses this hypercall to move contents of each page of
+ the VM from normal memory to secure memory.
+
+ #. Ultravisor uses this hypercall to ask Hypervisor to provide a page
+ in normal memory that can be shared between the SVM and Hypervisor.
+
+ #. Ultravisor uses this hypercall to page-in a paged-out page. This
+ can happen when the SVM touches a paged-out page.
+
+ #. If SVM wants to disable sharing of pages with Hypervisor, it can
+ inform Ultravisor to do so. Ultravisor will then use this hypercall
+ and inform Hypervisor that it has released access to the normal
+ page.
+
+H_SVM_PAGE_OUT
+---------------
+
+ Move the contents of the page to normal memory.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t hypercall(const uint64_t H_SVM_PAGE_OUT,
+ uint64_t guest_pa, /* guest-physical-address */
+ uint64_t flags, /* flags (currently none) */
+ uint64_t order) /* page size order */
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * H_SUCCESS on success.
+ * H_PARAMETER if ``guest_pa`` is invalid.
+ * H_P2 if ``flags`` is invalid.
+ * H_P3 if ``order`` is invalid.
+
+Description
+~~~~~~~~~~~
+
+ Move the contents of the page identified by ``guest_pa`` to normal
+ memory.
+
+ Currently ``flags`` is unused and must be set to 0. The ``order``
+ parameter must correspond to the configured page size.
+
+Use cases
+~~~~~~~~~
+
+ #. If Ultravisor is running low on secure pages, it can move the
+ contents of some secure pages, into normal pages using this
+ hypercall. The content will be encrypted.
+
+References
+##########
+
+.. [1] `Supporting Protected Computing on IBM Power Architecture <https://developer.ibm.com/articles/l-support-protected-computing/>`_

2019-09-02 03:32:13

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH v4 02/16] powerpc/pseries: Introduce option to build secure virtual machines

On Tue, 2019-08-20 at 02:13:12 UTC, Thiago Jung Bauermann wrote:
> Introduce CONFIG_PPC_SVM to control support for secure guests and include
> Ultravisor-related helpers when it is selected
>
> Signed-off-by: Thiago Jung Bauermann <[email protected]>

Patch 2-14 & 16 applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/136bc0397ae21dbf63ca02e5775ad353a479cd2f

cheers

2019-09-03 18:55:36

by Thiago Jung Bauermann

[permalink] [raw]
Subject: Re: [PATCH v4 02/16] powerpc/pseries: Introduce option to build secure virtual machines


Michael Ellerman <[email protected]> writes:

> On Tue, 2019-08-20 at 02:13:12 UTC, Thiago Jung Bauermann wrote:
>> Introduce CONFIG_PPC_SVM to control support for secure guests and include
>> Ultravisor-related helpers when it is selected
>>
>> Signed-off-by: Thiago Jung Bauermann <[email protected]>
>
> Patch 2-14 & 16 applied to powerpc next, thanks.
>
> https://git.kernel.org/powerpc/c/136bc0397ae21dbf63ca02e5775ad353a479cd2f

Thank you very much!

--
Thiago Jung Bauermann
IBM Linux Technology Center

2019-09-05 05:00:30

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH v4 02/16] powerpc/pseries: Introduce option to build secure virtual machines

Thiago Jung Bauermann <[email protected]> writes:
> Michael Ellerman <[email protected]> writes:
>> On Tue, 2019-08-20 at 02:13:12 UTC, Thiago Jung Bauermann wrote:
>>> Introduce CONFIG_PPC_SVM to control support for secure guests and include
>>> Ultravisor-related helpers when it is selected
>>>
>>> Signed-off-by: Thiago Jung Bauermann <[email protected]>
>>
>> Patch 2-14 & 16 applied to powerpc next, thanks.
>>
>> https://git.kernel.org/powerpc/c/136bc0397ae21dbf63ca02e5775ad353a479cd2f
>
> Thank you very much!

No worries. I meant to say, there were some minor differences between
your patch 15 adding the documentation and Claudio's version. If you
want those differences applied please send me an incremental patch.

cheers

2019-09-05 19:03:50

by Thiago Jung Bauermann

[permalink] [raw]
Subject: Re: [PATCH v4 02/16] powerpc/pseries: Introduce option to build secure virtual machines


Hi Michael,

Michael Ellerman <[email protected]> writes:

> Thiago Jung Bauermann <[email protected]> writes:
>> Michael Ellerman <[email protected]> writes:
>>> On Tue, 2019-08-20 at 02:13:12 UTC, Thiago Jung Bauermann wrote:
>>>> Introduce CONFIG_PPC_SVM to control support for secure guests and include
>>>> Ultravisor-related helpers when it is selected
>>>>
>>>> Signed-off-by: Thiago Jung Bauermann <[email protected]>
>>>
>>> Patch 2-14 & 16 applied to powerpc next, thanks.
>>>
>>> https://git.kernel.org/powerpc/c/136bc0397ae21dbf63ca02e5775ad353a479cd2f
>>
>> Thank you very much!
>
> No worries. I meant to say, there were some minor differences between
> your patch 15 adding the documentation and Claudio's version. If you
> want those differences applied please send me an incremental patch.

Thanks for pointing it out. There's no need. Claudio's version is the
canonical one. The differences are because I had a slightly older
version at the time I posted my patches.

--
Thiago Jung Bauermann
IBM Linux Technology Center