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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>,
	Brijesh Singh <brijesh.singh@amd.com>,
	Michael Roth <michael.roth@amd.com>,
	Jiewen Yao <Jiewen.yao@intel.com>
Subject: [PATCH v10 12/32] OvmfPkg/PlatformPei: register GHCB gpa for the SEV-SNP guest
Date: Tue, 19 Oct 2021 14:39:14 -0500	[thread overview]
Message-ID: <20211019193934.1052465-13-brijesh.singh@amd.com> (raw)
In-Reply-To: <20211019193934.1052465-1-brijesh.singh@amd.com>

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

The SEV-SNP guest requires that GHCB GPA must be registered before using.
See the GHCB specification section 2.3.2 for more details.

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>
---
 OvmfPkg/PlatformPei/AmdSev.c | 91 ++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)

diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
index a8bf610022ba..de876fdb478e 100644
--- a/OvmfPkg/PlatformPei/AmdSev.c
+++ b/OvmfPkg/PlatformPei/AmdSev.c
@@ -19,9 +19,93 @@
 #include <PiPei.h>
 #include <Register/Amd/Msr.h>
 #include <Register/Intel/SmramSaveStateMap.h>
+#include <Library/VmgExitLib.h>
 
 #include "Platform.h"
 
+/**
+  Handle an SEV-SNP/GHCB protocol check failure.
+
+  Notify the hypervisor using the VMGEXIT instruction that the SEV-SNP guest
+  wishes to be terminated.
+
+  @param[in] ReasonCode  Reason code to provide to the hypervisor for the
+                         termination request.
+
+**/
+STATIC
+VOID
+SevEsProtocolFailure (
+  IN UINT8  ReasonCode
+  )
+{
+  MSR_SEV_ES_GHCB_REGISTER  Msr;
+
+  //
+  // Use the GHCB MSR Protocol to request termination by the hypervisor
+  //
+  Msr.GhcbPhysicalAddress = 0;
+  Msr.GhcbTerminate.Function = GHCB_INFO_TERMINATE_REQUEST;
+  Msr.GhcbTerminate.ReasonCodeSet = GHCB_TERMINATE_GHCB;
+  Msr.GhcbTerminate.ReasonCode = ReasonCode;
+  AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+  AsmVmgExit ();
+
+  ASSERT (FALSE);
+  CpuDeadLoop ();
+}
+
+/**
+
+  This function can be used to register the GHCB GPA.
+
+  @param[in]  Address           The physical address to be registered.
+
+**/
+STATIC
+VOID
+GhcbRegister (
+  IN  EFI_PHYSICAL_ADDRESS   Address
+  )
+{
+  MSR_SEV_ES_GHCB_REGISTER  Msr;
+  MSR_SEV_ES_GHCB_REGISTER  CurrentMsr;
+  EFI_PHYSICAL_ADDRESS      GuestFrameNumber;
+
+  GuestFrameNumber = Address >> EFI_PAGE_SHIFT;
+
+  //
+  // Save the current MSR Value
+  //
+  CurrentMsr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+
+  //
+  // Use the GHCB MSR Protocol to request to register the GPA.
+  //
+  Msr.GhcbPhysicalAddress = 0;
+  Msr.GhcbGpaRegister.Function = GHCB_INFO_GHCB_GPA_REGISTER_REQUEST;
+  Msr.GhcbGpaRegister.GuestFrameNumber = GuestFrameNumber;
+  AsmWriteMsr64 (MSR_SEV_ES_GHCB, Msr.GhcbPhysicalAddress);
+
+  AsmVmgExit ();
+
+  Msr.GhcbPhysicalAddress = AsmReadMsr64 (MSR_SEV_ES_GHCB);
+
+  //
+  // If hypervisor responded with a different GPA than requested then fail.
+  //
+  if ((Msr.GhcbGpaRegister.Function != GHCB_INFO_GHCB_GPA_REGISTER_RESPONSE) ||
+      (Msr.GhcbGpaRegister.GuestFrameNumber != GuestFrameNumber)) {
+    SevEsProtocolFailure (GHCB_TERMINATE_GHCB_GENERAL);
+  }
+
+  //
+  // Restore the MSR
+  //
+  AsmWriteMsr64 (MSR_SEV_ES_GHCB, CurrentMsr.GhcbPhysicalAddress);
+}
+
 /**
 
   Initialize SEV-ES support if running as an SEV-ES guest.
@@ -109,6 +193,13 @@ AmdSevEsInitialize (
     "SEV-ES is enabled, %lu GHCB backup pages allocated starting at 0x%p\n",
     (UINT64)GhcbBackupPageCount, GhcbBackupBase));
 
+  //
+  // SEV-SNP guest requires that GHCB GPA must be registered before using it.
+  //
+  if (MemEncryptSevSnpIsEnabled ()) {
+    GhcbRegister (GhcbBasePa);
+  }
+
   AsmWriteMsr64 (MSR_SEV_ES_GHCB, GhcbBasePa);
 
   //
-- 
2.25.1


  parent reply	other threads:[~2021-10-19 19:40 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-19 19:39 [PATCH v10 00/32] Add AMD Secure Nested Paging (SEV-SNP) support Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 01/32] OvmfPkg/SecMain: move SEV specific routines in AmdSev.c Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 02/32] UefiCpuPkg/MpInitLib: " Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 03/32] OvmfPkg/ResetVector: move clearing GHCB in SecMain Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 04/32] OvmfPkg/ResetVector: introduce SEV metadata descriptor for VMM use Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 05/32] OvmfPkg: reserve SNP secrets page Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 06/32] OvmfPkg: reserve CPUID page Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 07/32] OvmfPkg/ResetVector: pre-validate the data pages used in SEC phase Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 08/32] OvmfPkg/ResetVector: use SEV-SNP-validated CPUID values Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 09/32] OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled() Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 10/32] OvmfPkg/SecMain: register GHCB gpa for the SEV-SNP guest Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 11/32] OvmfPkg/VmgExitLib: use SEV-SNP-validated CPUID values Brijesh Singh
2021-10-19 19:39 ` Brijesh Singh [this message]
2021-10-19 19:39 ` [PATCH v10 13/32] OvmfPkg/AmdSevDxe: do not use extended PCI config space Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 14/32] OvmfPkg/MemEncryptSevLib: add support to validate system RAM Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 15/32] OvmfPkg/MemEncryptSevLib: add function to check the VMPL0 Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 16/32] OvmfPkg/BaseMemEncryptSevLib: skip the pre-validated system RAM Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 17/32] OvmfPkg/MemEncryptSevLib: add support to validate > 4GB memory in PEI phase Brijesh Singh
2021-10-20  4:54   ` Gerd Hoffmann
2021-10-19 19:39 ` [PATCH v10 18/32] OvmfPkg/SecMain: validate the memory used for decompressing Fv Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 19/32] OvmfPkg/PlatformPei: validate the system RAM when SNP is active Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 20/32] UefiCpuPkg: Define ConfidentialComputingGuestAttr Brijesh Singh
2021-10-20  4:55   ` Gerd Hoffmann
2021-10-19 19:39 ` [PATCH v10 21/32] OvmfPkg/PlatformPei: set PcdConfidentialComputingAttr when SEV is active Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 22/32] UefiCpuPkg/MpInitLib: use PcdConfidentialComputingAttr to check SEV status Brijesh Singh
2021-10-20  4:58   ` Gerd Hoffmann
2021-10-19 19:39 ` [PATCH v10 23/32] UefiCpuPkg: add PcdGhcbHypervisorFeatures Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 24/32] OvmfPkg/PlatformPei: set the Hypervisor Features PCD Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 25/32] MdePkg/GHCB: increase the GHCB protocol max version Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 26/32] UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is enabled Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 27/32] UefiCpuPkg/MpInitLib: use BSP to do extended topology check Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 28/32] OvmfPkg/MemEncryptSevLib: change the page state in the RMP table Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 29/32] OvmfPkg/MemEncryptSevLib: skip page state change for Mmio address Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 30/32] OvmfPkg/PlatformPei: mark cpuid and secrets memory reserved in EFI map Brijesh Singh
2021-10-20  5:00   ` Gerd Hoffmann
2021-10-19 19:39 ` [PATCH v10 31/32] OvmfPkg/AmdSev: expose the SNP reserved pages through configuration table Brijesh Singh
2021-10-19 19:39 ` [PATCH v10 32/32] UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation NAE event to launch APs Brijesh Singh

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