This series enables Linux guests running on Hyper-V on ARM64
hardware. New ARM64-specific code in arch/arm64/hyperv initializes
Hyper-V, including its interrupts and hypercall mechanism.
Existing architecture independent drivers for Hyper-V's VMbus and
synthetic devices just work when built for ARM64. Hyper-V code is
built and included in the image and modules only if CONFIG_HYPERV
is enabled.
The seven patches are organized as follows:
1) Update include/linux/arm-smccc.h to provide an HVC wrapper
variant that returns results in other than X0 thru X3
2) Add definitions and functions for making Hyper-V hypercalls
and getting/setting virtual processor registers provided by
Hyper-V
3) Add architecture specific definitions needed by the
architecture independent Hyper-V clocksource driver in
drivers/clocksource/hyperv_timer.c. Update the clocksource
driver to be initialized on ARM64.
4) Add functions needed by the arch independent VMbus driver
for reporting a panic to Hyper-V and as stubs for the kexec
and crash handlers.
5) Add Hyper-V initialization code and utility functions that
report Hyper-v status.
6) Export screen_info so it may be used by the Hyper-V frame buffer
driver built as a module. It is already exported for x86,
powerpc, and alpha architectures.
7) Make CONFIG_HYPERV selectable on ARM64 in addition to x86/x64.
Hyper-V on ARM64 runs with a 4 Kbyte page size, but allows guests
with 4K/16K/64K page size. Linux guests with this ARM64 enablement
code work with all three supported ARM64 page sizes.
The Hyper-V vPCI driver at drivers/pci/host/pci-hyperv.c has
x86/x64-specific code and is not being built for ARM64. Fixing
this driver to enable vPCI devices on ARM64 will be done later.
In a few cases, terminology from the x86/x64 world has been carried
over into the ARM64 code ("MSR", "TSC"). Hyper-V still uses the
x86/x64 terminology and has not replaced it with something more
generic, so the code uses the Hyper-V terminology. This will be
fixed when Hyper-V updates the usage in the TLFS.
This patch set is based on the hyperv-next branch of the code tree
https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/
Changes in v9:
* Added Patch 1 to enable making an SMCCC compliant hypercall
that returns results in other than registers X0 thru X3, per
version 1.2 and later of the SMCCC spec.
* Using the ability to return results in registers X6 and X7,
converted hv_get_vpreg_128() to use a "fast" hypercall that
passes inputs and outputs in registers, and in doing so eliminated
a lot of memory allocation complexity.
* Cleaned up some extra blank lines and use of spaces in aligning
local variables. [Sunil Muthuswamy]
* Based on discussion about future directions, reverted the
population of hv_vp_index array to use a cpuhp state instead
of a hypercall, which is like it was in v7 and earlier.
Changes in v8:
* Removed a lot of code based on refactoring the boundary between
arch independent and arch dependent code for Hyper-V, per comments
from Arnd Bergmann. The removed code was either duplicated on
the x86 side, or has been folded into architecture independent
code as not really being architecture dependent.
* Added config dependency on !CONFIG_CPU_BIG_ENDIAN [Arnd Bergmann]
* Reworked the approach to Hyper-V initialization. The functionality
is the same, but is now structured like the Xen code with an early
init function called in setup_arch() and an early initcall to
finish the initialization. [Arnd Bergmann]
Changes in v7:
* Separately upstreamed split of hyperv-tlfs.h into arch dependent
and independent versions. In this patch set, update the ARM64
hyperv-tlfs.h to include architecture independent definitions.
This approach eliminates a lot of lines of otherwise duplicated
code on the ARM64 side.
* Break ARM64 mshyperv.h into smaller pieces. Have an initial
baseline, and add code along with patches for a particular
functional area. [Marc Zyngier]
* In mshyperv.h, use static inline functions instead of #defines
where possible. [Arnd Bergmann]
* Use VMbus INTID obtained from ACPI DSDT instead of hardcoding.
The STIMER INTID is still hardcoded because it is needed
before Linux has initialized the ACPI subsystem, so it can't
be obtained from the DSDT. Wedging it into the GTDT seems
dubious, so was not done. [Marc Zyngier]
* Update Hyper-V page size allocation functions to use
alloc_page() if PAGE_SIZE == HV_HYP_PAGE_SIZE [Arnd
Bergmann]
* Various other minor changes based on feedback and to rebase
to latest linux-next [Marc Zyngier and Arnd Bergmann]
Changes in v6:
* Use SMCCC hypercall interface instead of direct invocation
of HVC instruction and the Hyper-V hypercall interface
[Marc Zyngier]
* Reimplemented functions to alloc/free Hyper-V size pages
using kmalloc/kfree since kmalloc now guarantees alignment of
power of 2 size allocations [Marc Zyngier]
* Export screen_info in arm64 architecture so it can be used
by the Hyper-V buffer driver built as a module
* Renamed source file arch/arm64/hyperv/hv_init.c to hv_core.c
to better reflect its content
* Fixed the bit position of certain feature flags presented by
Hyper-V to the guest. The bit positions on ARM64 don't match
the position on x86 like originally thought.
* Minor fixups to rebase to 5.6-rc5 linux-next
Changes in v5:
* Minor fixups to rebase to 5.4-rc1 linux-next
Changes in v4:
* Moved clock-related code into an architecture independent
Hyper-V clocksource driver that is already upstream. Clock
related code is removed from this patch set except for the
ARM64 specific interrupt handler. [Marc Zyngier]
* Separately upstreamed the split of mshyperv.h into arch independent
and arch dependent portions. The arch independent portion has been
removed from this patch set.
* Divided patch #2 of the series into multiple smaller patches
[Marc Zyngier]
* Changed a dozen or so smaller things based on feedback
[Marc Zyngier, Will Deacon]
* Added functions to alloc/free Hyper-V size pages for use by
drivers for Hyper-V synthetic devices when updated to not assume
guest page size and Hyper-v page size are the same
Changes in v3:
* Added initialization of hv_vp_index array like was recently
added on x86 branch [KY Srinivasan]
* Changed Hyper-V ARM64 register symbols to be all uppercase
instead of mixed case [KY Srinivasan]
* Separated mshyperv.h into two files, one architecture
independent and one architecture dependent. After this code
is upstream, will make changes to the x86 code to use the
architecture independent file and remove duplication. And
once we have a multi-architecture Hyper-V TLFS, will do a
separate patch to split hyperv-tlfs.h in the same way.
[KY Srinivasan]
* Minor tweaks to rebase to latest linux-next code
Changes in v2:
* Removed patch to implement slow_virt_to_phys() on ARM64.
Use of slow_virt_to_phys() in arch independent Hyper-V
drivers has been eliminated by commit 6ba34171bcbd
("Drivers: hv: vmbus: Remove use of slow_virt_to_phys()")
* Minor tweaks to rebase to latest linux-next code
*** BLURB HERE ***
Michael Kelley (7):
smccc: Add HVC call variant with result registers other than 0 thru 3
arm64: hyperv: Add Hyper-V hypercall and register access utilities
arm64: hyperv: Add Hyper-V clocksource/clockevent support
arm64: hyperv: Add kexec and panic handlers
arm64: hyperv: Initialize hypervisor on boot
arm64: efi: Export screen_info
Drivers: hv: Enable Hyper-V code to be built on ARM64
MAINTAINERS | 3 +
arch/arm64/Kbuild | 1 +
arch/arm64/hyperv/Makefile | 2 +
arch/arm64/hyperv/hv_core.c | 178 +++++++++++++++++++++++++++++++++++
arch/arm64/hyperv/mshyperv.c | 173 ++++++++++++++++++++++++++++++++++
arch/arm64/include/asm/hyperv-tlfs.h | 69 ++++++++++++++
arch/arm64/include/asm/mshyperv.h | 72 ++++++++++++++
arch/arm64/kernel/efi.c | 1 +
arch/arm64/kernel/setup.c | 4 +
drivers/clocksource/hyperv_timer.c | 14 +++
drivers/hv/Kconfig | 3 +-
include/linux/arm-smccc.h | 29 ++++--
12 files changed, 542 insertions(+), 7 deletions(-)
create mode 100644 arch/arm64/hyperv/Makefile
create mode 100644 arch/arm64/hyperv/hv_core.c
create mode 100644 arch/arm64/hyperv/mshyperv.c
create mode 100644 arch/arm64/include/asm/hyperv-tlfs.h
create mode 100644 arch/arm64/include/asm/mshyperv.h
--
1.8.3.1
Add architecture specific definitions and functions needed
by the architecture independent Hyper-V clocksource driver.
Update the Hyper-V clocksource driver to be initialized
on ARM64.
Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Sunil Muthuswamy <[email protected]>
---
arch/arm64/include/asm/mshyperv.h | 12 ++++++++++++
drivers/clocksource/hyperv_timer.c | 14 ++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
index c448704..b17299c 100644
--- a/arch/arm64/include/asm/mshyperv.h
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -21,6 +21,7 @@
#include <linux/types.h>
#include <linux/arm-smccc.h>
#include <asm/hyperv-tlfs.h>
+#include <clocksource/arm_arch_timer.h>
/*
* Declare calls to get and set Hyper-V VP register values on ARM64, which
@@ -41,6 +42,17 @@ static inline u64 hv_get_register(unsigned int reg)
return hv_get_vpreg(reg);
}
+/* Define the interrupt ID used by STIMER0 Direct Mode interrupts. This
+ * value can't come from ACPI tables because it is needed before the
+ * Linux ACPI subsystem is initialized.
+ */
+#define HYPERV_STIMER0_VECTOR 31
+
+static inline u64 hv_get_raw_timer(void)
+{
+ return arch_timer_read_counter();
+}
+
/* SMCCC hypercall parameters */
#define HV_SMCCC_FUNC_NUMBER 1
#define HV_FUNC_ID ARM_SMCCC_CALL_VAL( \
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index ba04cb3..044efb1 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -473,3 +473,17 @@ void __init hv_init_clocksource(void)
hv_setup_sched_clock(read_hv_sched_clock_msr);
}
EXPORT_SYMBOL_GPL(hv_init_clocksource);
+
+/* Initialize everything on ARM64 */
+static int __init hyperv_timer_init(struct acpi_table_header *table)
+{
+ if (!hv_is_hyperv_initialized())
+ return -EINVAL;
+
+ hv_init_clocksource();
+ if (hv_stimer_alloc(true))
+ return -EINVAL;
+
+ return 0;
+}
+TIMER_ACPI_DECLARE(hyperv, ACPI_SIG_GTDT, hyperv_timer_init);
--
1.8.3.1
Add function to inform Hyper-V about a guest panic.
Also add functions to set up and remove kexec and panic
handlers, which are currently unused on ARM64 but are
called from architecture independent code in the VMbus
driver.
This code is built only when CONFIG_HYPERV is enabled.
Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Sunil Muthuswamy <[email protected]>
---
arch/arm64/hyperv/Makefile | 2 +-
arch/arm64/hyperv/hv_core.c | 52 ++++++++++++++++++++++++++++++++++++++++++
arch/arm64/hyperv/mshyperv.c | 54 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 107 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/hyperv/mshyperv.c
diff --git a/arch/arm64/hyperv/Makefile b/arch/arm64/hyperv/Makefile
index 1697d30..87c31c0 100644
--- a/arch/arm64/hyperv/Makefile
+++ b/arch/arm64/hyperv/Makefile
@@ -1,2 +1,2 @@
# SPDX-License-Identifier: GPL-2.0
-obj-y := hv_core.o
+obj-y := hv_core.o mshyperv.o
diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
index d5a8a6e..fdcd69f 100644
--- a/arch/arm64/hyperv/hv_core.c
+++ b/arch/arm64/hyperv/hv_core.c
@@ -124,3 +124,55 @@ u64 hv_get_vpreg(u32 msr)
return output.as64.low;
}
EXPORT_SYMBOL_GPL(hv_get_vpreg);
+
+/*
+ * hyperv_report_panic - report a panic to Hyper-V. This function uses
+ * the older version of the Hyper-V interface that admittedly doesn't
+ * pass enough information to be useful beyond just recording the
+ * occurrence of a panic. The parallel hv_kmsg_dump() uses the
+ * new interface that allows reporting 4 Kbytes of data, which is much
+ * more useful. Hyper-V on ARM64 always supports the newer interface, but
+ * we retain support for the older version because the sysadmin is allowed
+ * to disable the newer version via sysctl in case of information security
+ * concerns about the more verbose version.
+ */
+void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
+{
+ static bool panic_reported;
+ u64 guest_id;
+
+ /* Don't report a panic to Hyper-V if we're not going to panic */
+ if (in_die && !panic_on_oops)
+ return;
+
+ /*
+ * We prefer to report panic on 'die' chain as we have proper
+ * registers to report, but if we miss it (e.g. on BUG()) we need
+ * to report it on 'panic'.
+ *
+ * Calling code in the 'die' and 'panic' paths ensures that only
+ * one CPU is running this code, so no atomicity is needed.
+ */
+ if (panic_reported)
+ return;
+ panic_reported = true;
+
+ guest_id = hv_get_vpreg(HV_REGISTER_GUEST_OSID);
+
+ /*
+ * Hyper-V provides the ability to store only 5 values.
+ * Pick the passed in error value, the guest_id, and the PC.
+ * The first two general registers are added arbitrarily.
+ */
+ hv_set_vpreg(HV_REGISTER_CRASH_P0, err);
+ hv_set_vpreg(HV_REGISTER_CRASH_P1, guest_id);
+ hv_set_vpreg(HV_REGISTER_CRASH_P2, regs->pc);
+ hv_set_vpreg(HV_REGISTER_CRASH_P3, regs->regs[0]);
+ hv_set_vpreg(HV_REGISTER_CRASH_P4, regs->regs[1]);
+
+ /*
+ * Let Hyper-V know there is crash data available
+ */
+ hv_set_vpreg(HV_REGISTER_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
+}
+EXPORT_SYMBOL_GPL(hyperv_report_panic);
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
new file mode 100644
index 0000000..d202b4c
--- /dev/null
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Core routines for interacting with Microsoft's Hyper-V hypervisor.
+ * Includes hypervisor initialization, and handling of crashes and
+ * kexecs through a set of static "handler" variables set by the
+ * architecture independent VMbus driver.
+ *
+ * Copyright (C) 2021, Microsoft, Inc.
+ *
+ * Author : Michael Kelley <[email protected]>
+ */
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/ptrace.h>
+
+/*
+ * The VMbus handler functions are no-ops on ARM64 because
+ * VMbus interrupts are handled as percpu IRQs.
+ */
+void hv_setup_vmbus_handler(void (*handler)(void))
+{
+}
+EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);
+
+void hv_remove_vmbus_handler(void)
+{
+}
+EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);
+
+/*
+ * The kexec and crash handler functions are
+ * currently no-ops on ARM64.
+ */
+void hv_setup_kexec_handler(void (*handler)(void))
+{
+}
+EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
+
+void hv_remove_kexec_handler(void)
+{
+}
+EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
+
+void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
+{
+}
+EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
+
+void hv_remove_crash_handler(void)
+{
+}
+EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
--
1.8.3.1
hyperv-tlfs.h defines Hyper-V interfaces from the Hyper-V Top Level
Functional Spec (TLFS), and #includes the architecture-independent
part of hyperv-tlfs.h in include/asm-generic. The published TLFS
is distinctly oriented to x86/x64, so the ARM64-specific
hyperv-tlfs.h includes information for ARM64 that is not yet formally
published. The TLFS is available here:
docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs
mshyperv.h defines Linux-specific structures and routines for
interacting with Hyper-V on ARM64, and #includes the architecture-
independent part of mshyperv.h in include/asm-generic.
Use these definitions to provide utility functions to make
Hyper-V hypercalls and to get and set Hyper-V provided
registers associated with a virtual processor.
Signed-off-by: Michael Kelley <[email protected]>
---
MAINTAINERS | 3 +
arch/arm64/Kbuild | 1 +
arch/arm64/hyperv/Makefile | 2 +
arch/arm64/hyperv/hv_core.c | 126 +++++++++++++++++++++++++++++++++++
arch/arm64/include/asm/hyperv-tlfs.h | 69 +++++++++++++++++++
arch/arm64/include/asm/mshyperv.h | 54 +++++++++++++++
6 files changed, 255 insertions(+)
create mode 100644 arch/arm64/hyperv/Makefile
create mode 100644 arch/arm64/hyperv/hv_core.c
create mode 100644 arch/arm64/include/asm/hyperv-tlfs.h
create mode 100644 arch/arm64/include/asm/mshyperv.h
diff --git a/MAINTAINERS b/MAINTAINERS
index bfc1b86..7a47a90 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8232,6 +8232,9 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
F: Documentation/ABI/stable/sysfs-bus-vmbus
F: Documentation/ABI/testing/debugfs-hyperv
F: Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst
+F: arch/arm64/hyperv
+F: arch/arm64/include/asm/hyperv-tlfs.h
+F: arch/arm64/include/asm/mshyperv.h
F: arch/x86/hyperv
F: arch/x86/include/asm/hyperv-tlfs.h
F: arch/x86/include/asm/mshyperv.h
diff --git a/arch/arm64/Kbuild b/arch/arm64/Kbuild
index d646582..7a37608 100644
--- a/arch/arm64/Kbuild
+++ b/arch/arm64/Kbuild
@@ -3,4 +3,5 @@ obj-y += kernel/ mm/
obj-$(CONFIG_NET) += net/
obj-$(CONFIG_KVM) += kvm/
obj-$(CONFIG_XEN) += xen/
+obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/
obj-$(CONFIG_CRYPTO) += crypto/
diff --git a/arch/arm64/hyperv/Makefile b/arch/arm64/hyperv/Makefile
new file mode 100644
index 0000000..1697d30
--- /dev/null
+++ b/arch/arm64/hyperv/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y := hv_core.o
diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
new file mode 100644
index 0000000..d5a8a6e
--- /dev/null
+++ b/arch/arm64/hyperv/hv_core.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Low level utility routines for interacting with Hyper-V.
+ *
+ * Copyright (C) 2021, Microsoft, Inc.
+ *
+ * Author : Michael Kelley <[email protected]>
+ */
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/hyperv.h>
+#include <linux/arm-smccc.h>
+#include <linux/module.h>
+#include <asm-generic/bug.h>
+#include <asm/hyperv-tlfs.h>
+#include <asm/mshyperv.h>
+
+/*
+ * hv_do_hypercall- Invoke the specified hypercall
+ */
+u64 hv_do_hypercall(u64 control, void *input, void *output)
+{
+ struct arm_smccc_res res;
+ u64 input_address;
+ u64 output_address;
+
+ input_address = input ? virt_to_phys(input) : 0;
+ output_address = output ? virt_to_phys(output) : 0;
+
+ arm_smccc_1_1_hvc(HV_FUNC_ID, control,
+ input_address, output_address, &res);
+ return res.a0;
+}
+EXPORT_SYMBOL_GPL(hv_do_hypercall);
+
+/*
+ * hv_do_fast_hypercall8 -- Invoke the specified hypercall
+ * with arguments in registers instead of physical memory.
+ * Avoids the overhead of virt_to_phys for simple hypercalls.
+ */
+
+u64 hv_do_fast_hypercall8(u16 code, u64 input)
+{
+ struct arm_smccc_res res;
+ u64 control;
+
+ control = (u64)code | HV_HYPERCALL_FAST_BIT;
+
+ arm_smccc_1_1_hvc(HV_FUNC_ID, control, input, &res);
+ return res.a0;
+}
+EXPORT_SYMBOL_GPL(hv_do_fast_hypercall8);
+
+/*
+ * Set a single VP register to a 64-bit value.
+ */
+void hv_set_vpreg(u32 msr, u64 value)
+{
+ struct arm_smccc_res res;
+
+ arm_smccc_1_1_hvc(
+ HV_FUNC_ID,
+ HVCALL_SET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |
+ HV_HYPERCALL_REP_COMP_1,
+ HV_PARTITION_ID_SELF,
+ HV_VP_INDEX_SELF,
+ msr,
+ 0,
+ value,
+ 0,
+ &res);
+
+ /*
+ * Something is fundamentally broken in the hypervisor if
+ * setting a VP register fails. There's really no way to
+ * continue as a guest VM, so panic.
+ */
+ BUG_ON((res.a0 & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS);
+}
+EXPORT_SYMBOL_GPL(hv_set_vpreg);
+
+/*
+ * Get the value of a single VP register. One version
+ * returns just 64 bits and another returns the full 128 bits.
+ * The two versions are separate to avoid complicating the
+ * calling sequence for the more frequently used 64 bit version.
+ */
+
+void hv_get_vpreg_128(u32 msr, struct hv_get_vp_registers_output *result)
+{
+ struct arm_smccc_res res;
+
+ arm_smccc_1_1_hvc_reg("r5", "r6", "r7",
+ HV_FUNC_ID,
+ HVCALL_GET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |
+ HV_HYPERCALL_REP_COMP_1,
+ HV_PARTITION_ID_SELF,
+ HV_VP_INDEX_SELF,
+ msr,
+ 0,
+ &res);
+
+ /*
+ * Something is fundamentally broken in the hypervisor if
+ * getting a VP register fails. There's really no way to
+ * continue as a guest VM, so panic.
+ */
+ BUG_ON((res.a0 & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS);
+
+ result->as64.low = res.a2; /* r6 */
+ result->as64.high = res.a3; /* r7 */
+}
+EXPORT_SYMBOL_GPL(hv_get_vpreg_128);
+
+u64 hv_get_vpreg(u32 msr)
+{
+ struct hv_get_vp_registers_output output;
+
+ hv_get_vpreg_128(msr, &output);
+
+ return output.as64.low;
+}
+EXPORT_SYMBOL_GPL(hv_get_vpreg);
diff --git a/arch/arm64/include/asm/hyperv-tlfs.h b/arch/arm64/include/asm/hyperv-tlfs.h
new file mode 100644
index 0000000..4d964a7
--- /dev/null
+++ b/arch/arm64/include/asm/hyperv-tlfs.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * This file contains definitions from the Hyper-V Hypervisor Top-Level
+ * Functional Specification (TLFS):
+ * https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs
+ *
+ * Copyright (C) 2021, Microsoft, Inc.
+ *
+ * Author : Michael Kelley <[email protected]>
+ */
+
+#ifndef _ASM_HYPERV_TLFS_H
+#define _ASM_HYPERV_TLFS_H
+
+#include <linux/types.h>
+
+/*
+ * All data structures defined in the TLFS that are shared between Hyper-V
+ * and a guest VM use Little Endian byte ordering. This matches the default
+ * byte ordering of Linux running on ARM64, so no special handling is required.
+ */
+
+/*
+ * These Hyper-V registers provide information equivalent to the CPUID
+ * instruction on x86/x64.
+ */
+#define HV_REGISTER_HYPERVISOR_VERSION 0x00000100 /*CPUID 0x40000002 */
+#define HV_REGISTER_FEATURES 0x00000200 /*CPUID 0x40000003 */
+#define HV_REGISTER_ENLIGHTENMENTS 0x00000201 /*CPUID 0x40000004 */
+
+/*
+ * Group C Features. See the asm-generic version of hyperv-tlfs.h
+ * for a description of Feature Groups.
+ */
+
+/* Crash MSRs available */
+#define HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE BIT(8)
+
+/* STIMER direct mode is available */
+#define HV_STIMER_DIRECT_MODE_AVAILABLE BIT(13)
+
+/*
+ * Synthetic register definitions equivalent to MSRs on x86/x64
+ */
+#define HV_REGISTER_CRASH_P0 0x00000210
+#define HV_REGISTER_CRASH_P1 0x00000211
+#define HV_REGISTER_CRASH_P2 0x00000212
+#define HV_REGISTER_CRASH_P3 0x00000213
+#define HV_REGISTER_CRASH_P4 0x00000214
+#define HV_REGISTER_CRASH_CTL 0x00000215
+
+#define HV_REGISTER_GUEST_OSID 0x00090002
+#define HV_REGISTER_VP_INDEX 0x00090003
+#define HV_REGISTER_TIME_REF_COUNT 0x00090004
+#define HV_REGISTER_REFERENCE_TSC 0x00090017
+
+#define HV_REGISTER_SINT0 0x000A0000
+#define HV_REGISTER_SCONTROL 0x000A0010
+#define HV_REGISTER_SIEFP 0x000A0012
+#define HV_REGISTER_SIMP 0x000A0013
+#define HV_REGISTER_EOM 0x000A0014
+
+#define HV_REGISTER_STIMER0_CONFIG 0x000B0000
+#define HV_REGISTER_STIMER0_COUNT 0x000B0001
+
+#include <asm-generic/hyperv-tlfs.h>
+
+#endif
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
new file mode 100644
index 0000000..c448704
--- /dev/null
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Linux-specific definitions for managing interactions with Microsoft's
+ * Hyper-V hypervisor. The definitions in this file are specific to
+ * the ARM64 architecture. See include/asm-generic/mshyperv.h for
+ * definitions are that architecture independent.
+ *
+ * Definitions that are specified in the Hyper-V Top Level Functional
+ * Spec (TLFS) should not go in this file, but should instead go in
+ * hyperv-tlfs.h.
+ *
+ * Copyright (C) 2021, Microsoft, Inc.
+ *
+ * Author : Michael Kelley <[email protected]>
+ */
+
+#ifndef _ASM_MSHYPERV_H
+#define _ASM_MSHYPERV_H
+
+#include <linux/types.h>
+#include <linux/arm-smccc.h>
+#include <asm/hyperv-tlfs.h>
+
+/*
+ * Declare calls to get and set Hyper-V VP register values on ARM64, which
+ * requires a hypercall.
+ */
+
+extern void hv_set_vpreg(u32 reg, u64 value);
+extern u64 hv_get_vpreg(u32 reg);
+extern void hv_get_vpreg_128(u32 reg, struct hv_get_vp_registers_output *result);
+
+static inline void hv_set_register(unsigned int reg, u64 value)
+{
+ hv_set_vpreg(reg, value);
+}
+
+static inline u64 hv_get_register(unsigned int reg)
+{
+ return hv_get_vpreg(reg);
+}
+
+/* SMCCC hypercall parameters */
+#define HV_SMCCC_FUNC_NUMBER 1
+#define HV_FUNC_ID ARM_SMCCC_CALL_VAL( \
+ ARM_SMCCC_STD_CALL, \
+ ARM_SMCCC_SMC_64, \
+ ARM_SMCCC_OWNER_VENDOR_HYP, \
+ HV_SMCCC_FUNC_NUMBER)
+
+#include <asm-generic/mshyperv.h>
+
+#endif
--
1.8.3.1
Add ARM64-specific code to initialize the Hyper-V
hypervisor when booting as a guest VM. Provide functions
and data structures indicating hypervisor status that
are needed by VMbus driver.
This code is built only when CONFIG_HYPERV is enabled.
Signed-off-by: Michael Kelley <[email protected]>
---
arch/arm64/hyperv/mshyperv.c | 119 ++++++++++++++++++++++++++++++++++++++
arch/arm64/include/asm/mshyperv.h | 6 ++
arch/arm64/kernel/setup.c | 4 ++
3 files changed, 129 insertions(+)
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index d202b4c..125e83e 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -14,6 +14,125 @@
#include <linux/types.h>
#include <linux/export.h>
#include <linux/ptrace.h>
+#include <linux/errno.h>
+#include <linux/acpi.h>
+#include <linux/version.h>
+#include <linux/cpuhotplug.h>
+#include <linux/slab.h>
+#include <linux/cpumask.h>
+#include <asm/mshyperv.h>
+
+static bool hyperv_initialized;
+struct ms_hyperv_info ms_hyperv __ro_after_init;
+EXPORT_SYMBOL_GPL(ms_hyperv);
+
+u32 *hv_vp_index;
+EXPORT_SYMBOL_GPL(hv_vp_index);
+
+u32 hv_max_vp_index;
+EXPORT_SYMBOL_GPL(hv_max_vp_index);
+
+static int hv_cpu_init(unsigned int cpu)
+{
+ hv_vp_index[cpu] = hv_get_vpreg(HV_REGISTER_VP_INDEX);
+ return 0;
+}
+
+void __init hyperv_early_init(void)
+{
+ struct hv_get_vp_registers_output result;
+ u32 a, b, c, d;
+ u64 guest_id;
+
+ /*
+ * If we're in a VM on Hyper-V, the ACPI hypervisor_id field will
+ * have the string "MsHyperV".
+ */
+ if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))
+ return;
+
+ /* Setup the guest ID */
+ guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
+ hv_set_vpreg(HV_REGISTER_GUEST_OSID, guest_id);
+
+ /* Get the features and hints from Hyper-V */
+ hv_get_vpreg_128(HV_REGISTER_FEATURES, &result);
+ ms_hyperv.features = result.as32.a;
+ ms_hyperv.misc_features = result.as32.c;
+
+ hv_get_vpreg_128(HV_REGISTER_ENLIGHTENMENTS, &result);
+ ms_hyperv.hints = result.as32.a;
+
+ pr_info("Hyper-V: Features 0x%x, hints 0x%x, misc 0x%x\n",
+ ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features);
+
+ /*
+ * If Hyper-V has crash notifications, set crash_kexec_post_notifiers
+ * so that we will report the panic to Hyper-V before running kdump.
+ */
+ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
+ crash_kexec_post_notifiers = true;
+
+ /* Get information about the Hyper-V host version */
+ hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result);
+ a = result.as32.a;
+ b = result.as32.b;
+ c = result.as32.c;
+ d = result.as32.d;
+ pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
+ b >> 16, b & 0xFFFF, a, d & 0xFFFFFF, c, d >> 24);
+
+ hyperv_initialized = true;
+}
+
+static int __init hyperv_init(void)
+{
+ int i;
+
+ /* Allocate and initialize percpu VP index array */
+ hv_max_vp_index = num_possible_cpus();
+ hv_vp_index = kmalloc_array(hv_max_vp_index, sizeof(*hv_vp_index),
+ GFP_KERNEL);
+ if (!hv_vp_index) {
+ hv_max_vp_index = 0;
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < hv_max_vp_index; i++)
+ hv_vp_index[i] = VP_INVAL;
+
+ if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/hyperv_init:online",
+ hv_cpu_init, NULL) < 0) {
+ hv_max_vp_index = 0;
+ kfree(hv_vp_index);
+ hv_vp_index = NULL;
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+early_initcall(hyperv_init);
+
+/* This routine is called before kexec/kdump. It does required cleanup. */
+void hyperv_cleanup(void)
+{
+ hv_set_vpreg(HV_REGISTER_GUEST_OSID, 0);
+
+}
+EXPORT_SYMBOL_GPL(hyperv_cleanup);
+
+bool hv_is_hyperv_initialized(void)
+{
+ return hyperv_initialized;
+}
+EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
+
+bool hv_is_hibernation_supported(void)
+{
+ return false;
+}
+EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
/*
* The VMbus handler functions are no-ops on ARM64 because
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
index b17299c..86ca5c5 100644
--- a/arch/arm64/include/asm/mshyperv.h
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -23,6 +23,12 @@
#include <asm/hyperv-tlfs.h>
#include <clocksource/arm_arch_timer.h>
+#if IS_ENABLED(CONFIG_HYPERV)
+void __init hyperv_early_init(void);
+#else
+static inline void hyperv_early_init(void) {};
+#endif
+
/*
* Declare calls to get and set Hyper-V VP register values on ARM64, which
* requires a hypercall.
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index c18aacd..1df8285 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -49,6 +49,7 @@
#include <asm/traps.h>
#include <asm/efi.h>
#include <asm/xen/hypervisor.h>
+#include <asm/mshyperv.h>
#include <asm/mmu_context.h>
static int num_standard_resources;
@@ -340,6 +341,9 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
if (acpi_disabled)
unflatten_device_tree();
+ /* Do after acpi_boot_table_init() so local FADT is available */
+ hyperv_early_init();
+
bootmem_init();
kasan_init();
--
1.8.3.1
The Hyper-V frame buffer driver may be built as a module, and
it needs access to screen_info. So export screen_info.
Signed-off-by: Michael Kelley <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
---
arch/arm64/kernel/efi.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index fa02efb..e1be6c4 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -55,6 +55,7 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
/* we will fill this structure from the stub, so don't put it in .bss */
struct screen_info screen_info __section(".data");
+EXPORT_SYMBOL(screen_info);
int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
{
--
1.8.3.1
Update drivers/hv/Kconfig so CONFIG_HYPERV can be selected on
ARM64, causing the Hyper-V specific code to be built.
Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Sunil Muthuswamy <[email protected]>
---
drivers/hv/Kconfig | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 79e5356..d492682 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -4,7 +4,8 @@ menu "Microsoft Hyper-V guest support"
config HYPERV
tristate "Microsoft Hyper-V client drivers"
- depends on X86 && ACPI && X86_LOCAL_APIC && HYPERVISOR_GUEST
+ depends on ACPI && ((X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
+ || (ARM64 && !CPU_BIG_ENDIAN))
select PARAVIRT
select X86_HV_CALLBACK_VECTOR
help
--
1.8.3.1
> static int num_standard_resources;
> @@ -340,6 +341,9 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
> if (acpi_disabled)
> unflatten_device_tree();
>
> + /* Do after acpi_boot_table_init() so local FADT is available */
> + hyperv_early_init();
> +
> bootmem_init();
>
> kasan_init();
> --
> 1.8.3.1
Reviewed-by: Sunil Muthuswamy <[email protected]>
> +static inline u64 hv_get_register(unsigned int reg)
> +{
> + return hv_get_vpreg(reg);
> +}
> +
> +/* SMCCC hypercall parameters */
> +#define HV_SMCCC_FUNC_NUMBER 1
> +#define HV_FUNC_ID ARM_SMCCC_CALL_VAL( \
> + ARM_SMCCC_STD_CALL, \
> + ARM_SMCCC_SMC_64, \
> + ARM_SMCCC_OWNER_VENDOR_HYP, \
> + HV_SMCCC_FUNC_NUMBER)
> +
> +#include <asm-generic/mshyperv.h>
> +
> +#endif
> --
> 1.8.3.1
Reviewed-by: Sunil Muthuswamy <[email protected]>
From: Michael Kelley <[email protected]> Sent: Monday, March 8, 2021 11:57 AM
>
> This series enables Linux guests running on Hyper-V on ARM64
> hardware. New ARM64-specific code in arch/arm64/hyperv initializes
> Hyper-V, including its interrupts and hypercall mechanism.
> Existing architecture independent drivers for Hyper-V's VMbus and
> synthetic devices just work when built for ARM64. Hyper-V code is
> built and included in the image and modules only if CONFIG_HYPERV
> is enabled.
ARM64 maintainers --
What are the prospects for getting your review and Ack on this patch set?
We're wanting to get the Hyper-V support on ARM64 finally accepted upstream.
Previous comments should be addressed in this revision, with perhaps a
remaining discussion point around the alternate SMCCC hypercall interface
in Patch 1 that makes use of changes in v1.2 of the SMCCC spec. There are
several viable approaches that I've noted in the patch, depending on
your preferences.
Michael
>
> The seven patches are organized as follows:
>
> 1) Update include/linux/arm-smccc.h to provide an HVC wrapper
> variant that returns results in other than X0 thru X3
>
> 2) Add definitions and functions for making Hyper-V hypercalls
> and getting/setting virtual processor registers provided by
> Hyper-V
>
> 3) Add architecture specific definitions needed by the
> architecture independent Hyper-V clocksource driver in
> drivers/clocksource/hyperv_timer.c. Update the clocksource
> driver to be initialized on ARM64.
>
> 4) Add functions needed by the arch independent VMbus driver
> for reporting a panic to Hyper-V and as stubs for the kexec
> and crash handlers.
>
> 5) Add Hyper-V initialization code and utility functions that
> report Hyper-v status.
>
> 6) Export screen_info so it may be used by the Hyper-V frame buffer
> driver built as a module. It is already exported for x86,
> powerpc, and alpha architectures.
>
> 7) Make CONFIG_HYPERV selectable on ARM64 in addition to x86/x64.
>
> Hyper-V on ARM64 runs with a 4 Kbyte page size, but allows guests
> with 4K/16K/64K page size. Linux guests with this ARM64 enablement
> code work with all three supported ARM64 page sizes.
>
> The Hyper-V vPCI driver at drivers/pci/host/pci-hyperv.c has
> x86/x64-specific code and is not being built for ARM64. Fixing
> this driver to enable vPCI devices on ARM64 will be done later.
>
> In a few cases, terminology from the x86/x64 world has been carried
> over into the ARM64 code ("MSR", "TSC"). Hyper-V still uses the
> x86/x64 terminology and has not replaced it with something more
> generic, so the code uses the Hyper-V terminology. This will be
> fixed when Hyper-V updates the usage in the TLFS.
>
> This patch set is based on the hyperv-next branch of the code tree
> https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/
>
> Changes in v9:
> * Added Patch 1 to enable making an SMCCC compliant hypercall
> that returns results in other than registers X0 thru X3, per
> version 1.2 and later of the SMCCC spec.
> * Using the ability to return results in registers X6 and X7,
> converted hv_get_vpreg_128() to use a "fast" hypercall that
> passes inputs and outputs in registers, and in doing so eliminated
> a lot of memory allocation complexity.
> * Cleaned up some extra blank lines and use of spaces in aligning
> local variables. [Sunil Muthuswamy]
> * Based on discussion about future directions, reverted the
> population of hv_vp_index array to use a cpuhp state instead
> of a hypercall, which is like it was in v7 and earlier.
>
> Changes in v8:
> * Removed a lot of code based on refactoring the boundary between
> arch independent and arch dependent code for Hyper-V, per comments
> from Arnd Bergmann. The removed code was either duplicated on
> the x86 side, or has been folded into architecture independent
> code as not really being architecture dependent.
> * Added config dependency on !CONFIG_CPU_BIG_ENDIAN [Arnd Bergmann]
> * Reworked the approach to Hyper-V initialization. The functionality
> is the same, but is now structured like the Xen code with an early
> init function called in setup_arch() and an early initcall to
> finish the initialization. [Arnd Bergmann]
>
> Changes in v7:
> * Separately upstreamed split of hyperv-tlfs.h into arch dependent
> and independent versions. In this patch set, update the ARM64
> hyperv-tlfs.h to include architecture independent definitions.
> This approach eliminates a lot of lines of otherwise duplicated
> code on the ARM64 side.
> * Break ARM64 mshyperv.h into smaller pieces. Have an initial
> baseline, and add code along with patches for a particular
> functional area. [Marc Zyngier]
> * In mshyperv.h, use static inline functions instead of #defines
> where possible. [Arnd Bergmann]
> * Use VMbus INTID obtained from ACPI DSDT instead of hardcoding.
> The STIMER INTID is still hardcoded because it is needed
> before Linux has initialized the ACPI subsystem, so it can't
> be obtained from the DSDT. Wedging it into the GTDT seems
> dubious, so was not done. [Marc Zyngier]
> * Update Hyper-V page size allocation functions to use
> alloc_page() if PAGE_SIZE == HV_HYP_PAGE_SIZE [Arnd
> Bergmann]
> * Various other minor changes based on feedback and to rebase
> to latest linux-next [Marc Zyngier and Arnd Bergmann]
>
> Changes in v6:
> * Use SMCCC hypercall interface instead of direct invocation
> of HVC instruction and the Hyper-V hypercall interface
> [Marc Zyngier]
> * Reimplemented functions to alloc/free Hyper-V size pages
> using kmalloc/kfree since kmalloc now guarantees alignment of
> power of 2 size allocations [Marc Zyngier]
> * Export screen_info in arm64 architecture so it can be used
> by the Hyper-V buffer driver built as a module
> * Renamed source file arch/arm64/hyperv/hv_init.c to hv_core.c
> to better reflect its content
> * Fixed the bit position of certain feature flags presented by
> Hyper-V to the guest. The bit positions on ARM64 don't match
> the position on x86 like originally thought.
> * Minor fixups to rebase to 5.6-rc5 linux-next
>
> Changes in v5:
> * Minor fixups to rebase to 5.4-rc1 linux-next
>
> Changes in v4:
> * Moved clock-related code into an architecture independent
> Hyper-V clocksource driver that is already upstream. Clock
> related code is removed from this patch set except for the
> ARM64 specific interrupt handler. [Marc Zyngier]
> * Separately upstreamed the split of mshyperv.h into arch independent
> and arch dependent portions. The arch independent portion has been
> removed from this patch set.
> * Divided patch #2 of the series into multiple smaller patches
> [Marc Zyngier]
> * Changed a dozen or so smaller things based on feedback
> [Marc Zyngier, Will Deacon]
> * Added functions to alloc/free Hyper-V size pages for use by
> drivers for Hyper-V synthetic devices when updated to not assume
> guest page size and Hyper-v page size are the same
>
> Changes in v3:
> * Added initialization of hv_vp_index array like was recently
> added on x86 branch [KY Srinivasan]
> * Changed Hyper-V ARM64 register symbols to be all uppercase
> instead of mixed case [KY Srinivasan]
> * Separated mshyperv.h into two files, one architecture
> independent and one architecture dependent. After this code
> is upstream, will make changes to the x86 code to use the
> architecture independent file and remove duplication. And
> once we have a multi-architecture Hyper-V TLFS, will do a
> separate patch to split hyperv-tlfs.h in the same way.
> [KY Srinivasan]
> * Minor tweaks to rebase to latest linux-next code
>
> Changes in v2:
> * Removed patch to implement slow_virt_to_phys() on ARM64.
> Use of slow_virt_to_phys() in arch independent Hyper-V
> drivers has been eliminated by commit 6ba34171bcbd
> ("Drivers: hv: vmbus: Remove use of slow_virt_to_phys()")
> * Minor tweaks to rebase to latest linux-next code
> *** BLURB HERE ***
>
> Michael Kelley (7):
> smccc: Add HVC call variant with result registers other than 0 thru 3
> arm64: hyperv: Add Hyper-V hypercall and register access utilities
> arm64: hyperv: Add Hyper-V clocksource/clockevent support
> arm64: hyperv: Add kexec and panic handlers
> arm64: hyperv: Initialize hypervisor on boot
> arm64: efi: Export screen_info
> Drivers: hv: Enable Hyper-V code to be built on ARM64
>
> MAINTAINERS | 3 +
> arch/arm64/Kbuild | 1 +
> arch/arm64/hyperv/Makefile | 2 +
> arch/arm64/hyperv/hv_core.c | 178 +++++++++++++++++++++++++++++++++++
> arch/arm64/hyperv/mshyperv.c | 173 ++++++++++++++++++++++++++++++++++
> arch/arm64/include/asm/hyperv-tlfs.h | 69 ++++++++++++++
> arch/arm64/include/asm/mshyperv.h | 72 ++++++++++++++
> arch/arm64/kernel/efi.c | 1 +
> arch/arm64/kernel/setup.c | 4 +
> drivers/clocksource/hyperv_timer.c | 14 +++
> drivers/hv/Kconfig | 3 +-
> include/linux/arm-smccc.h | 29 ++++--
> 12 files changed, 542 insertions(+), 7 deletions(-)
> create mode 100644 arch/arm64/hyperv/Makefile
> create mode 100644 arch/arm64/hyperv/hv_core.c
> create mode 100644 arch/arm64/hyperv/mshyperv.c
> create mode 100644 arch/arm64/include/asm/hyperv-tlfs.h
> create mode 100644 arch/arm64/include/asm/mshyperv.h
>
> --
> 1.8.3.1
From: Michael Kelley <[email protected]>
> Sent: Wednesday, March 24, 2021 8:55 AM
> To: [email protected]; [email protected]; Mark Rutland <[email protected]>;
> [email protected]; [email protected]
> Cc: [email protected]; [email protected]; linux-
> [email protected]; [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; KY Srinivasan <[email protected]>
> Subject: RE: [PATCH v9 0/7] Enable Linux guests on Hyper-V on ARM64
>
> From: Michael Kelley <[email protected]> Sent: Monday, March 8, 2021 11:57 AM
> >
> > This series enables Linux guests running on Hyper-V on ARM64
> > hardware. New ARM64-specific code in arch/arm64/hyperv initializes
> > Hyper-V, including its interrupts and hypercall mechanism.
> > Existing architecture independent drivers for Hyper-V's VMbus and
> > synthetic devices just work when built for ARM64. Hyper-V code is
> > built and included in the image and modules only if CONFIG_HYPERV
> > is enabled.
>
> ARM64 maintainers --
>
> What are the prospects for getting your review and Ack on this patch set?
> We're wanting to get the Hyper-V support on ARM64 finally accepted upstream.
> Previous comments should be addressed in this revision, with perhaps a
> remaining discussion point around the alternate SMCCC hypercall interface
> in Patch 1 that makes use of changes in v1.2 of the SMCCC spec. There are
> several viable approaches that I've noted in the patch, depending on
> your preferences.
>
> Michael
Thanks, Mark, for jumping in on the SMCCC hypercall interface. But I'm still
looking for feedback or ACKs on the other patches in the series. There's only
one place in Patch 2 of the series that needs the SMCCC v1.2 interface, and I'd
like to be able to respond to any remaining issues with the other patches
while the SMCCC details are finished up.
Michael