Re: [edk2-devel] [PATCH v3 16/24] UefiCpuPkg/MpInitLib: Use AmdSvsmSnpVmsaRmpAdjust() to set/clear VMSA

["Ni, Ray" <ray.ni@intel.com>]

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Acked-by: Ray Ni <ray.ni@intel.com>

Thanks,
Ray
________________________________
From: Tom Lendacky <thomas.lendacky@amd.com>
Sent: Friday, March 8, 2024 23:29
To: devel@edk2.groups.io <devel@edk2.groups.io>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>; Aktas, Erdem <erdemaktas@google.com>; Gerd Hoffmann <kraxel@redhat.com>; Yao, Jiewen <jiewen.yao@intel.com>; Laszlo Ersek <lersek@redhat.com>; Liming Gao <gaoliming@byosoft.com.cn>; Kinney, Michael D <michael.d.kinney@intel.com>; Xu, Min M <min.m.xu@intel.com>; Liu, Zhiguang <zhiguang.liu@intel.com>; Kumar, Rahul R <rahul.r.kumar@intel.com>; Ni, Ray <ray.ni@intel.com>; Michael Roth <michael.roth@amd.com>
Subject: [PATCH v3 16/24] UefiCpuPkg/MpInitLib: Use AmdSvsmSnpVmsaRmpAdjust() to set/clear VMSA

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

The RMPADJUST instruction is used to change the VMSA attribute of a page,
but the VMSA attribute can only be changed when running at VMPL0. To
prepare for running at a less priviledged VMPL, use the AmdSvsmLib library
API to perform the RMPADJUST. The AmdSvsmLib library will perform the
proper operation on behalf of the caller.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf |  1 +
 UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf |  1 +
 UefiCpuPkg/Library/MpInitLib/MpLib.h          | 14 -----
 UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c    | 20 --------
 UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c     | 54 +++-----------------
 5 files changed, 9 insertions(+), 81 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
index 69950fcd1289..19745437f005 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
@@ -57,6 +57,7 @@ [LibraryClasses]
   SynchronizationLib
   PcdLib
   CcExitLib
+  AmdSvsmLib
   MicrocodeLib
 [LibraryClasses.X64]
   CpuPageTableLib
diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
index 22f74a814534..679e51a1acd5 100644
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
@@ -53,6 +53,7 @@ [LibraryClasses]
   PeiServicesLib
   PcdLib
   CcExitLib
+  AmdSvsmLib
   MicrocodeLib

 [Pcd]
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 65e05c4806f5..179f8e585b5d 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -883,20 +883,6 @@ FillExchangeInfoDataSevEs (
   IN volatile MP_CPU_EXCHANGE_INFO  *ExchangeInfo
   );

-/**
-  Issue RMPADJUST to adjust the VMSA attribute of an SEV-SNP page.
-
-  @param[in]  PageAddress
-  @param[in]  VmsaPage
-
-  @return  RMPADJUST return value
-**/
-UINT32
-SevSnpRmpAdjust (
-  IN  EFI_PHYSICAL_ADDRESS  PageAddress,
-  IN  BOOLEAN               VmsaPage
-  );
-
 /**
   Create an SEV-SNP AP save area (VMSA) for use in running the vCPU.

diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
index 0478e92317f1..963bd62494b9 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
@@ -49,26 +49,6 @@ SevSnpCreateAP (
   ASSERT (FALSE);
 }

-/**
-  Issue RMPADJUST to adjust the VMSA attribute of an SEV-SNP page.
-
-  @param[in]  PageAddress
-  @param[in]  VmsaPage
-
-  @return  RMPADJUST return value
-**/
-UINT32
-SevSnpRmpAdjust (
-  IN  EFI_PHYSICAL_ADDRESS  PageAddress,
-  IN  BOOLEAN               VmsaPage
-  )
-{
-  //
-  // RMPADJUST is not supported in 32-bit mode
-  //
-  return RETURN_UNSUPPORTED;
-}
-
 /**
   Determine if the SEV-SNP AP Create protocol should be used.

diff --git a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
index bd12a5ee2fcb..981135621384 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
+++ b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
@@ -10,6 +10,7 @@

 #include "MpLib.h"
 #include <Library/CcExitLib.h>
+#include <Library/AmdSvsmLib.h>
 #include <Register/Amd/Fam17Msr.h>
 #include <Register/Amd/Ghcb.h>

@@ -38,20 +39,15 @@ SevSnpPerformApAction (
   BOOLEAN                   InterruptState;
   UINT64                    ExitInfo1;
   UINT64                    ExitInfo2;
-  UINT32                    RmpAdjustStatus;
   UINT64                    VmgExitStatus;
+  EFI_STATUS                VmsaStatus;

   if (Action == SVM_VMGEXIT_SNP_AP_CREATE) {
     //
-    // To turn the page into a recognized VMSA page, issue RMPADJUST:
-    //   Target VMPL but numerically higher than current VMPL
-    //   Target PermissionMask is not used
+    // Turn the page into a recognized VMSA page.
     //
-    RmpAdjustStatus = SevSnpRmpAdjust (
-                        (EFI_PHYSICAL_ADDRESS)(UINTN)SaveArea,
-                        TRUE
-                        );
-    if (RmpAdjustStatus != 0) {
+    VmsaStatus = AmdSvsmSnpVmsaRmpAdjust (SaveArea, ApicId, TRUE);
+    if (EFI_ERROR (VmsaStatus)) {
       DEBUG ((DEBUG_INFO, "SEV-SNP: RMPADJUST failed for VMSA creation\n"));
       ASSERT (FALSE);

@@ -94,11 +90,8 @@ SevSnpPerformApAction (
     // Make the current VMSA not runnable and accessible to be
     // reprogrammed.
     //
-    RmpAdjustStatus = SevSnpRmpAdjust (
-                        (EFI_PHYSICAL_ADDRESS)(UINTN)SaveArea,
-                        FALSE
-                        );
-    if (RmpAdjustStatus != 0) {
+    VmsaStatus = AmdSvsmSnpVmsaRmpAdjust (SaveArea, ApicId, FALSE);
+    if (EFI_ERROR (VmsaStatus)) {
       DEBUG ((DEBUG_INFO, "SEV-SNP: RMPADJUST failed for VMSA reset\n"));
       ASSERT (FALSE);

@@ -328,39 +321,6 @@ SevSnpCreateAP (
   }
 }

-/**
-  Issue RMPADJUST to adjust the VMSA attribute of an SEV-SNP page.
-
-  @param[in]  PageAddress
-  @param[in]  VmsaPage
-
-  @return  RMPADJUST return value
-**/
-UINT32
-SevSnpRmpAdjust (
-  IN  EFI_PHYSICAL_ADDRESS  PageAddress,
-  IN  BOOLEAN               VmsaPage
-  )
-{
-  UINT64  Rdx;
-
-  //
-  // The RMPADJUST instruction is used to set or clear the VMSA bit for a
-  // page. The VMSA change is only made when running at VMPL0 and is ignored
-  // otherwise. If too low a target VMPL is specified, the instruction can
-  // succeed without changing the VMSA bit when not running at VMPL0. Using a
-  // target VMPL level of 1, RMPADJUST will return a FAIL_PERMISSION error if
-  // not running at VMPL0, thus ensuring that the VMSA bit is set appropriately
-  // when no error is returned.
-  //
-  Rdx = 1;
-  if (VmsaPage) {
-    Rdx |= RMPADJUST_VMSA_PAGE_BIT;
-  }
-
-  return AsmRmpAdjust ((UINT64)PageAddress, 0, Rdx);
-}
-
 /**
   Determine if the SEV-SNP AP Create protocol should be used.

--
2.43.2



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