Re: [edk2-devel] [PATCH v8 31/46] OvmfPkg: Create GHCB pages for use during Pei and Dxe phase
On 05/19/20 23:50, Lendacky, Thomas wrote:
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
>
> Allocate memory for the GHCB pages and the per-CPU variable pages during
> SEV initialization for use during Pei and Dxe phases. The GHCB page(s)
> must be shared pages, so clear the encryption mask from the current page
> table entries. Upon successful allocation, set the GHCB PCDs (PcdGhcbBase
> and PcdGhcbSize).
>
> The per-CPU variable page needs to be unique per AP. Using the page after
> the GHCB ensures that it is unique per AP. Only the GHCB page is marked as
> shared, keeping the per-CPU variable page encyrpted. The same logic is
> used in DXE using CreateIdentityMappingPageTables() before switching to
> the DXE pagetables.
>
> The GHCB pages (one per vCPU) will be used by the PEI and DXE #VC
> exception handlers. The #VC exception handler will fill in the necessary
> fields of the GHCB and exit to the hypervisor using the VMGEXIT
> instruction. The hypervisor then accesses the GHCB associated with the
> vCPU in order to perform the requested function.
>
> Cc: Jordan Justen
> Cc: Laszlo Ersek
> Cc: Ard Biesheuvel
> Reviewed-by: Laszlo Ersek
> Signed-off-by: Tom Lendacky
> ---
> OvmfPkg/OvmfPkgIa32.dsc | 2 ++
> OvmfPkg/OvmfPkgIa32X64.dsc | 2 ++
> OvmfPkg/OvmfPkgX64.dsc | 2 ++
> OvmfPkg/PlatformPei/PlatformPei.inf | 2 ++
> OvmfPkg/PlatformPei/AmdSev.c| 45 -
> 5 files changed, 52 insertions(+), 1 deletion(-)
>
> diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
> index b289260c1f2d..f849a7d698cd 100644
> --- a/OvmfPkg/OvmfPkgIa32.dsc
> +++ b/OvmfPkg/OvmfPkgIa32.dsc
> @@ -611,6 +611,8 @@ [PcdsDynamicDefault]
>gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
>
># Set SEV-ES defaults
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase|0
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize|0
>gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled|0
>
> !if $(SMM_REQUIRE) == TRUE
> diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
> index 00faf5036670..d1b4ffedc6af 100644
> --- a/OvmfPkg/OvmfPkgIa32X64.dsc
> +++ b/OvmfPkg/OvmfPkgIa32X64.dsc
> @@ -623,6 +623,8 @@ [PcdsDynamicDefault]
>gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
>
># Set SEV-ES defaults
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase|0
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize|0
>gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled|0
>
> !if $(SMM_REQUIRE) == TRUE
> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
> index 58671828c5fe..ebc903d922cf 100644
> --- a/OvmfPkg/OvmfPkgX64.dsc
> +++ b/OvmfPkg/OvmfPkgX64.dsc
> @@ -621,6 +621,8 @@ [PcdsDynamicDefault]
>gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
>
># Set SEV-ES defaults
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase|0
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize|0
>gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled|0
>
> !if $(SMM_REQUIRE) == TRUE
> diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf
> b/OvmfPkg/PlatformPei/PlatformPei.inf
> index a54d10ba90d5..4742e1bdf42b 100644
> --- a/OvmfPkg/PlatformPei/PlatformPei.inf
> +++ b/OvmfPkg/PlatformPei/PlatformPei.inf
> @@ -102,6 +102,8 @@ [Pcd]
>gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack
>gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiS3Enable
>gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase
> + gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize
>gEfiSecurityPkgTokenSpaceGuid.PcdOptionRomImageVerificationPolicy
>gUefiCpuPkgTokenSpaceGuid.PcdCpuLocalApicBaseAddress
>gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber
> diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
> index 4dc5340caa7a..4fd4534cabea 100644
> --- a/OvmfPkg/PlatformPei/AmdSev.c
> +++ b/OvmfPkg/PlatformPei/AmdSev.c
> @@ -10,12 +10,15 @@
> // The package level header files this module uses
> //
> #include
> +#include
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> +#include
> #include
> #include
>
> @@ -32,7 +35,10 @@ AmdSevEsInitialize (
>VOID
>)
> {
> - RETURN_STATUS PcdStatus;
> + VOID *GhcbBase;
> + PHYSICAL_ADDRESS GhcbBasePa;
> + UINTN GhcbPageCount, PageCount;
> + RETURN_STATUS PcdStatus, DecryptStatus;
>
>if (!MemEncryptSevEsIsEnabled ()) {
> return;
> @@ -40,6 +46,43 @@ AmdSevEsInitialize (
>
>PcdStatus = PcdSetBoolS (PcdSevEsIsEnabled, TRUE);
>ASSERT_RETURN_ERROR (PcdStatus);
> +
> + //
> + // Allocate GHCB and per-CPU variable pages.
> + //
> + GhcbPageCount = mMaxCpuCount * 2;
> + GhcbBase = AllocatePages (GhcbPageCount);
> + ASSERT (GhcbBase != NULL);
> +
> + GhcbBasePa = (PHYSICAL_ADDRESS)(UINTN) GhcbBase;
> +
> + //
> + // Each vCPU gets two consecutive pages, the first is the GHCB a
[edk2-devel] [PATCH v8 31/46] OvmfPkg: Create GHCB pages for use during Pei and Dxe phase
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
Allocate memory for the GHCB pages and the per-CPU variable pages during
SEV initialization for use during Pei and Dxe phases. The GHCB page(s)
must be shared pages, so clear the encryption mask from the current page
table entries. Upon successful allocation, set the GHCB PCDs (PcdGhcbBase
and PcdGhcbSize).
The per-CPU variable page needs to be unique per AP. Using the page after
the GHCB ensures that it is unique per AP. Only the GHCB page is marked as
shared, keeping the per-CPU variable page encyrpted. The same logic is
used in DXE using CreateIdentityMappingPageTables() before switching to
the DXE pagetables.
The GHCB pages (one per vCPU) will be used by the PEI and DXE #VC
exception handlers. The #VC exception handler will fill in the necessary
fields of the GHCB and exit to the hypervisor using the VMGEXIT
instruction. The hypervisor then accesses the GHCB associated with the
vCPU in order to perform the requested function.
Cc: Jordan Justen
Cc: Laszlo Ersek
Cc: Ard Biesheuvel
Reviewed-by: Laszlo Ersek
Signed-off-by: Tom Lendacky
---
OvmfPkg/OvmfPkgIa32.dsc | 2 ++
OvmfPkg/OvmfPkgIa32X64.dsc | 2 ++
OvmfPkg/OvmfPkgX64.dsc | 2 ++
OvmfPkg/PlatformPei/PlatformPei.inf | 2 ++
OvmfPkg/PlatformPei/AmdSev.c| 45 -
5 files changed, 52 insertions(+), 1 deletion(-)
diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index b289260c1f2d..f849a7d698cd 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -611,6 +611,8 @@ [PcdsDynamicDefault]
gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
# Set SEV-ES defaults
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase|0
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize|0
gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled|0
!if $(SMM_REQUIRE) == TRUE
diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
index 00faf5036670..d1b4ffedc6af 100644
--- a/OvmfPkg/OvmfPkgIa32X64.dsc
+++ b/OvmfPkg/OvmfPkgIa32X64.dsc
@@ -623,6 +623,8 @@ [PcdsDynamicDefault]
gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
# Set SEV-ES defaults
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase|0
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize|0
gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled|0
!if $(SMM_REQUIRE) == TRUE
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 58671828c5fe..ebc903d922cf 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -621,6 +621,8 @@ [PcdsDynamicDefault]
gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask|0x0
# Set SEV-ES defaults
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase|0
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize|0
gUefiCpuPkgTokenSpaceGuid.PcdSevEsIsEnabled|0
!if $(SMM_REQUIRE) == TRUE
diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf
b/OvmfPkg/PlatformPei/PlatformPei.inf
index a54d10ba90d5..4742e1bdf42b 100644
--- a/OvmfPkg/PlatformPei/PlatformPei.inf
+++ b/OvmfPkg/PlatformPei/PlatformPei.inf
@@ -102,6 +102,8 @@ [Pcd]
gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack
gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiS3Enable
gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbBase
+ gEfiMdeModulePkgTokenSpaceGuid.PcdGhcbSize
gEfiSecurityPkgTokenSpaceGuid.PcdOptionRomImageVerificationPolicy
gUefiCpuPkgTokenSpaceGuid.PcdCpuLocalApicBaseAddress
gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber
diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
index 4dc5340caa7a..4fd4534cabea 100644
--- a/OvmfPkg/PlatformPei/AmdSev.c
+++ b/OvmfPkg/PlatformPei/AmdSev.c
@@ -10,12 +10,15 @@
// The package level header files this module uses
//
#include
+#include
#include
#include
#include
+#include
#include
#include
#include
+#include
#include
#include
@@ -32,7 +35,10 @@ AmdSevEsInitialize (
VOID
)
{
- RETURN_STATUS PcdStatus;
+ VOID *GhcbBase;
+ PHYSICAL_ADDRESS GhcbBasePa;
+ UINTN GhcbPageCount, PageCount;
+ RETURN_STATUS PcdStatus, DecryptStatus;
if (!MemEncryptSevEsIsEnabled ()) {
return;
@@ -40,6 +46,43 @@ AmdSevEsInitialize (
PcdStatus = PcdSetBoolS (PcdSevEsIsEnabled, TRUE);
ASSERT_RETURN_ERROR (PcdStatus);
+
+ //
+ // Allocate GHCB and per-CPU variable pages.
+ //
+ GhcbPageCount = mMaxCpuCount * 2;
+ GhcbBase = AllocatePages (GhcbPageCount);
+ ASSERT (GhcbBase != NULL);
+
+ GhcbBasePa = (PHYSICAL_ADDRESS)(UINTN) GhcbBase;
+
+ //
+ // Each vCPU gets two consecutive pages, the first is the GHCB and the
+ // second is the per-CPU variable page. Loop through the allocation and
+ // only clear the encryption mask for the GHCB pages.
+ //
+ for (PageCount = 0; PageCount < GhcbPageCount; PageCount += 2) {
+DecryptStatus = MemEncryptSevClearPageEncMask (
+ 0,
+ GhcbBasePa + EFI_PAGES_TO_SI
