2012-10-11 21:53:31

by Mukesh Rathor

[permalink] [raw]
Subject: [PATCH V2 1/7]: PVH: basic and header changes, elfnote changes, ...


PVH: is a PV linux guest that has extended capabilities. This patch allows it to be configured and enabled. Also, basic header file changes to add new subcalls to physmap hypercall. Lastly, mfn_to_local_pfn must return mfn for paging mode translate

Signed-off-by: Mukesh R <[email protected]>
---
arch/x86/include/asm/xen/page.h | 3 +++
arch/x86/xen/Kconfig | 10 ++++++++++
arch/x86/xen/xen-head.S | 11 ++++++++++-
include/xen/interface/memory.h | 30 +++++++++++++++++++++++++++---
include/xen/interface/physdev.h | 10 ++++++++++
5 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 472b9b7..6af440d 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -159,6 +159,9 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine)
static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
{
unsigned long pfn = mfn_to_pfn(mfn);
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return mfn;
if (get_phys_to_machine(pfn) != mfn)
return -1; /* force !pfn_valid() */
return pfn;
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index fdce49c..9323b8c 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -50,3 +50,13 @@ config XEN_DEBUG_FS
Enable statistics output and various tuning options in debugfs.
Enabling this option may incur a significant performance overhead.

+config XEN_X86_PVH
+ bool "Support for running as a PVH guest (EXPERIMENTAL)"
+ depends on X86_64 && XEN && INTEL_IOMMU && EXPERIMENTAL
+ default n
+ help
+ This option enables support for running as a PVH guest (PV guest
+ using hardware extensions) under a suitably capable hypervisor.
+ This option is EXPERIMETNAL because the hypervisor interfaces
+ which it uses are not yet considered stable therefore backwards and
+ forwards compatibility is not yet guaranteed. If unsure, say N.
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index 7faed58..3e65ece 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -13,6 +13,15 @@
#include <xen/interface/elfnote.h>
#include <asm/xen/interface.h>

+#ifdef CONFIG_XEN_X86_PVH
+#define FEATURES_PVH "| writable_descriptor_tables" \
+ "| auto_translated_physmap" \
+ "| supervisor_mode_kernel" \
+ "| hvm_callback_vector"
+#else
+#define FEATURES_PVH /* Not supported */
+#endif
+
__INIT
ENTRY(startup_xen)
cld
@@ -95,7 +104,7 @@ NEXT_HYPERCALL(arch_6)
#endif
ELFNOTE(Xen, XEN_ELFNOTE_ENTRY, _ASM_PTR startup_xen)
ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
- ELFNOTE(Xen, XEN_ELFNOTE_FEATURES, .asciz "!writable_page_tables|pae_pgdir_above_4gb")
+ ELFNOTE(Xen, XEN_ELFNOTE_FEATURES, .asciz "!writable_page_tables|pae_pgdir_above_4gb"FEATURES_PVH)
ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "yes")
ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index d8e33a9..dbf4c6b 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -163,14 +163,22 @@ struct xen_add_to_physmap {
/* Which domain to change the mapping for. */
domid_t domid;

- /* Number of pages to go through for gmfn_range */
- uint16_t size;
-
+ union {
+ /* Number of pages to go through for gmfn_range */
+ uint16_t size;
+ /* IFF XENMAPSPACE_gmfn_foreign */
+ domid_t foreign_domid;
+ } u;
/* Source mapping space. */
#define XENMAPSPACE_shared_info 0 /* shared info page */
#define XENMAPSPACE_grant_table 1 /* grant table page */
+#define XENMAPSPACE_gmfn 2 /* GMFN */
+#define XENMAPSPACE_gmfn_range 3 /* GMFN range */
+#define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another guest */
unsigned int space;

+#define XENMAPIDX_grant_table_status 0x80000000
+
/* Index into source mapping space. */
unsigned long idx;

@@ -237,4 +245,20 @@ DEFINE_GUEST_HANDLE_STRUCT(xen_memory_map);
* during a driver critical region.
*/
extern spinlock_t xen_reservation_lock;
+
+/*
+ * Unmaps the page appearing at a particular GPFN from the specified guest's
+ * pseudophysical address space.
+ * arg == addr of xen_remove_from_physmap_t.
+ */
+#define XENMEM_remove_from_physmap 15
+struct xen_remove_from_physmap {
+ /* Which domain to change the mapping for. */
+ domid_t domid;
+
+ /* GPFN of the current mapping of the page. */
+ xen_pfn_t gpfn;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap);
+
#endif /* __XEN_PUBLIC_MEMORY_H__ */
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 9ce788d..3b9d5b6 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -258,6 +258,16 @@ struct physdev_pci_device {
uint8_t devfn;
};

+#define PHYSDEVOP_pvh_map_iomem 30
+struct physdev_map_iomem {
+ /* IN */
+ uint64_t first_gfn;
+ uint64_t first_mfn;
+ uint32_t nr_mfns;
+ uint32_t add_mapping; /* 1 == add mapping; 0 == unmap */
+
+};
+
/*
* Notify that some PIRQ-bound event channels have been unmasked.
* ** This command is obsolete since interface version 0x00030202 and is **
--
1.7.2.3


2012-10-12 08:48:52

by Ian Campbell

[permalink] [raw]
Subject: Re: [Xen-devel] [PATCH V2 1/7]: PVH: basic and header changes, elfnote changes, ...

On Thu, 2012-10-11 at 22:53 +0100, Mukesh Rathor wrote:
> PVH: is a PV linux guest that has extended capabilities. This patch allows it to be configured and enabled. Also, basic header file changes to add new subcalls to physmap hypercall. Lastly, mfn_to_local_pfn must return mfn for paging mode translate
>
> Signed-off-by: Mukesh R <[email protected]>

Since a S-o-b is a quasi-legal statement you probably ought to put your
full name here (I know it's obvious from the email address, but...)

> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index fdce49c..9323b8c 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -50,3 +50,13 @@ config XEN_DEBUG_FS
> Enable statistics output and various tuning options in debugfs.
> Enabling this option may incur a significant performance overhead.
>
> +config XEN_X86_PVH
> + bool "Support for running as a PVH guest (EXPERIMENTAL)"
> + depends on X86_64 && XEN && INTEL_IOMMU && EXPERIMENTAL

OOI why does the kernel side require an INTEL_IOMMU? I can see why the
hypervisor would need it but the guests (including dom0) can't actually
see the underlying IOMMU, can they?

> + default n
> + help
> + This option enables support for running as a PVH guest (PV guest
> + using hardware extensions) under a suitably capable hypervisor.
> + This option is EXPERIMETNAL because the hypervisor interfaces

You've carried over my original "EXPERIMETNAL" typo.

> + which it uses are not yet considered stable therefore backwards and
> + forwards compatibility is not yet guaranteed. If unsure, say N.
> diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
> index 7faed58..3e65ece 100644
> --- a/arch/x86/xen/xen-head.S
> +++ b/arch/x86/xen/xen-head.S
> @@ -13,6 +13,15 @@
> #include <xen/interface/elfnote.h>
> #include <asm/xen/interface.h>
>
> +#ifdef CONFIG_XEN_X86_PVH
> +#define FEATURES_PVH "| writable_descriptor_tables" \
> + "| auto_translated_physmap" \
> + "| supervisor_mode_kernel" \
> + "| hvm_callback_vector"

It's pretty lame but it looks like elf_xen_parse_features doesn't
support stripping whitespace.

Since we need these features to be parsable by older hypervisors and
tools I think we're stuck with that snafu.

> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> index 9ce788d..3b9d5b6 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -258,6 +258,16 @@ struct physdev_pci_device {
> uint8_t devfn;
> };
>
> +#define PHYSDEVOP_pvh_map_iomem 30
> +struct physdev_map_iomem {
> + /* IN */
> + uint64_t first_gfn;
> + uint64_t first_mfn;
> + uint32_t nr_mfns;
> + uint32_t add_mapping; /* 1 == add mapping; 0 == unmap */
> +
> +};
> +
> /*
> * Notify that some PIRQ-bound event channels have been unmasked.
> * ** This command is obsolete since interface version 0x00030202 and is **

2012-10-12 21:22:13

by Mukesh Rathor

[permalink] [raw]
Subject: Re: [Xen-devel] [PATCH V2 1/7]: PVH: basic and header changes, elfnote changes, ...

On Fri, 12 Oct 2012 09:48:48 +0100
Ian Campbell <[email protected]> wrote:

> > index fdce49c..9323b8c 100644
> > --- a/arch/x86/xen/Kconfig
> > +++ b/arch/x86/xen/Kconfig
> > @@ -50,3 +50,13 @@ config XEN_DEBUG_FS
> > Enable statistics output and various tuning options in
> > debugfs. Enabling this option may incur a significant performance
> > overhead.
> > +config XEN_X86_PVH
> > + bool "Support for running as a PVH guest (EXPERIMENTAL)"
> > + depends on X86_64 && XEN && INTEL_IOMMU && EXPERIMENTAL
>
> OOI why does the kernel side require an INTEL_IOMMU? I can see why the
> hypervisor would need it but the guests (including dom0) can't
> actually see the underlying IOMMU, can they?

Well, the kernel requires the hypervisor to have it, but I guess
thats not what this is referring to. The tools can decide that.
I'll take it out.