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From: "Brijesh Singh" <brijesh.singh@amd.com>
To: <devel@edk2.groups.io>
Cc: James Bottomley <jejb@linux.ibm.com>, Min Xu <min.m.xu@intel.com>,
	"Jiewen Yao" <jiewen.yao@intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"Jordan Justen" <jordan.l.justen@intel.com>,
	Ard Biesheuvel <ardb+tianocore@kernel.org>,
	Erdem Aktas <erdemaktas@google.com>,
	"Michael Roth" <Michael.Roth@amd.com>,
	Gerd Hoffmann <kraxel@redhat.com>,
	"Michael D Kinney" <michael.d.kinney@intel.com>,
	Liming Gao <gaoliming@byosoft.com.cn>,
	Zhiguang Liu <zhiguang.liu@intel.com>, Ray Ni <ray.ni@intel.com>,
	Rahul Kumar <rahul1.kumar@intel.com>,
	Eric Dong <eric.dong@intel.com>,
	Brijesh Singh <brijesh.singh@amd.com>,
	Michael Roth <michael.roth@amd.com>,
	Jiewen Yao <Jiewen.yao@intel.com>
Subject: [PATCH v14 28/32] OvmfPkg/MemEncryptSevLib: change the page state in the RMP table
Date: Wed, 8 Dec 2021 21:27:56 -0600	[thread overview]
Message-ID: <20211209032800.3802995-29-brijesh.singh@amd.com> (raw)
In-Reply-To: <20211209032800.3802995-1-brijesh.singh@amd.com>

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

The MemEncryptSev{Set,Clear}PageEncMask() functions are used to set or
clear the memory encryption attribute in the page table. When SEV-SNP
is active, we also need to change the page state in the RMP table so that
it is in sync with the memory encryption attribute change.

Cc: Michael Roth <michael.roth@amd.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 .../X64/PeiDxeVirtualMemory.c                 | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index f1485722f7cf..814f814035fa 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -17,6 +17,7 @@
 #include <Register/Cpuid.h>
 
 #include "VirtualMemory.h"
+#include "SnpPageStateChange.h"
 
 STATIC BOOLEAN          mAddressEncMaskChecked = FALSE;
 STATIC UINT64           mAddressEncMask;
@@ -693,10 +694,12 @@ SetMemoryEncDec (
   PAGE_MAP_AND_DIRECTORY_POINTER  *PageDirectoryPointerEntry;
   PAGE_TABLE_1G_ENTRY             *PageDirectory1GEntry;
   PAGE_TABLE_ENTRY                *PageDirectory2MEntry;
+  PHYSICAL_ADDRESS                OrigPhysicalAddress;
   PAGE_TABLE_4K_ENTRY             *PageTableEntry;
   UINT64                          PgTableMask;
   UINT64                          AddressEncMask;
   BOOLEAN                         IsWpEnabled;
+  UINTN                           OrigLength;
   RETURN_STATUS                   Status;
 
   //
@@ -749,6 +752,22 @@ SetMemoryEncDec (
 
   Status = EFI_SUCCESS;
 
+  //
+  // To maintain the security gurantees we must set the page to shared in the RMP
+  // table before clearing the memory encryption mask from the current page table.
+  //
+  // The InternalSetPageState() is used for setting the page state in the RMP table.
+  //
+  if ((Mode == ClearCBit) && MemEncryptSevSnpIsEnabled ()) {
+    InternalSetPageState (PhysicalAddress, EFI_SIZE_TO_PAGES (Length), SevSnpPageShared, FALSE);
+  }
+
+  //
+  // Save the specified length and physical address (we need it later).
+  //
+  OrigLength          = Length;
+  OrigPhysicalAddress = PhysicalAddress;
+
   while (Length != 0) {
     //
     // If Cr3BaseAddress is not specified then read the current CR3
@@ -922,6 +941,21 @@ SetMemoryEncDec (
   //
   CpuFlushTlb ();
 
+  //
+  // SEV-SNP requires that all the private pages (i.e pages mapped encrypted) must be
+  // added in the RMP table before the access.
+  //
+  // The InternalSetPageState() is used for setting the page state in the RMP table.
+  //
+  if ((Mode == SetCBit) && MemEncryptSevSnpIsEnabled ()) {
+    InternalSetPageState (
+      OrigPhysicalAddress,
+      EFI_SIZE_TO_PAGES (OrigLength),
+      SevSnpPagePrivate,
+      FALSE
+      );
+  }
+
 Done:
   //
   // Restore page table write protection, if any.
-- 
2.25.1


  parent reply	other threads:[~2021-12-09  3:29 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-09  3:27 [PATCH v14 00/32] Add AMD Secure Nested Paging (SEV-SNP) support Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 01/32] OvmfPkg/SecMain: move SEV specific routines in AmdSev.c Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 02/32] UefiCpuPkg/MpInitLib: " Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 03/32] OvmfPkg/ResetVector: move clearing GHCB in SecMain Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 04/32] OvmfPkg/ResetVector: introduce SEV metadata descriptor for VMM use Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 05/32] OvmfPkg: reserve SNP secrets page Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 06/32] OvmfPkg: reserve CPUID page Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 07/32] OvmfPkg/ResetVector: pre-validate the data pages used in SEC phase Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 08/32] OvmfPkg/ResetVector: use SEV-SNP-validated CPUID values Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 09/32] OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled() Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 10/32] OvmfPkg/SecMain: register GHCB gpa for the SEV-SNP guest Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 11/32] OvmfPkg/VmgExitLib: use SEV-SNP-validated CPUID values Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 12/32] OvmfPkg/PlatformPei: register GHCB gpa for the SEV-SNP guest Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 13/32] OvmfPkg/AmdSevDxe: do not use extended PCI config space Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 14/32] OvmfPkg/MemEncryptSevLib: add support to validate system RAM Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 15/32] OvmfPkg/MemEncryptSevLib: add function to check the VMPL0 Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 16/32] OvmfPkg/BaseMemEncryptSevLib: skip the pre-validated system RAM Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 17/32] OvmfPkg/MemEncryptSevLib: add support to validate > 4GB memory in PEI phase Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 18/32] OvmfPkg/SecMain: validate the memory used for decompressing Fv Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 19/32] OvmfPkg/PlatformPei: validate the system RAM when SNP is active Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 20/32] MdePkg: Define ConfidentialComputingGuestAttr Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 21/32] OvmfPkg/PlatformPei: set PcdConfidentialComputingAttr when SEV is active Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 22/32] UefiCpuPkg/MpInitLib: use PcdConfidentialComputingAttr to check SEV status Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 23/32] UefiCpuPkg: add PcdGhcbHypervisorFeatures Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 24/32] OvmfPkg/PlatformPei: set the Hypervisor Features PCD Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 25/32] MdePkg/GHCB: increase the GHCB protocol max version Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 26/32] UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is enabled Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 27/32] UefiCpuPkg/MpInitLib: use BSP to do extended topology check Brijesh Singh
2021-12-09  3:27 ` Brijesh Singh [this message]
2021-12-09  3:27 ` [PATCH v14 29/32] OvmfPkg/MemEncryptSevLib: skip page state change for Mmio address Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 30/32] OvmfPkg/PlatformPei: mark cpuid and secrets memory reserved in EFI map Brijesh Singh
2021-12-09  3:27 ` [PATCH v14 31/32] OvmfPkg/AmdSev: expose the SNP reserved pages through configuration table Brijesh Singh
2021-12-09  3:28 ` [PATCH v14 32/32] UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation NAE event to launch APs Brijesh Singh
2021-12-09  6:30 ` [edk2-devel] [PATCH v14 00/32] Add AMD Secure Nested Paging (SEV-SNP) support Yao, Jiewen

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