On 5/22/20 9:50 AM, Laszlo Ersek via groups.io wrote:
On 05/22/20 16:48, Laszlo Ersek wrote:
On 05/19/20 23:50, Lendacky, Thomas wrote:
BZ: 
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.tianocore.org%2Fshow_bug.cgi%3Fid%3D2198&data=02%7C01%7Cthomas.lendacky%40amd.com%7Cba73e0d6ccb9488ab10608d7fe5f7c8f%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637257558381229776&sdata=kwjA9Hgo1KKgY%2FarqEiQFDg5QVpx60Kfoh1AWqSuock%3D&reserved=0

Under SEV-ES, a VMMCALL intercept generates a #VC exception. VMGEXIT must
be used to allow the hypervisor to handle this intercept.

Cc: Jordan Justen <jordan.l.jus...@intel.com>
Cc: Laszlo Ersek <ler...@redhat.com>
Cc: Ard Biesheuvel <ard.biesheu...@arm.com>
Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
  .../Library/VmgExitLib/X64/VmgExitVcHandler.c | 48 +++++++++++++++++++
  1 file changed, 48 insertions(+)

diff --git a/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c 
b/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
index 0b7f24fd962c..bf1555234d69 100644
--- a/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
+++ b/OvmfPkg/Library/VmgExitLib/X64/VmgExitVcHandler.c
@@ -875,6 +875,50 @@ WbinvdExit (
    return 0;
  }
+/**
+  Handle a VMMCALL event.
+
+  Use the VMGEXIT instruction to handle either a VMMCALL event.

(2) pls drop the word "either".

I have this in a couple of places, so I'll take care of all of them.

Thanks!
TOm


Thanks
Laszlo

+
+  @param[in, out] Ghcb             Pointer to the Guest-Hypervisor 
Communication
+                                   Block
+  @param[in, out] Regs             x64 processor context
+  @param[in]      InstructionData  Instruction parsing context
+
+  @retval 0                        Event handled successfully
+  @retval Others                   New exception value to propagate
+
+**/
+STATIC
+UINT64
+VmmCallExit (
+  IN OUT GHCB                     *Ghcb,
+  IN OUT EFI_SYSTEM_CONTEXT_X64   *Regs,
+  IN     SEV_ES_INSTRUCTION_DATA  *InstructionData
+  )
+{
+  UINT64  Status;
+
+  DecodeModRm (Regs, InstructionData);
+
+  Ghcb->SaveArea.Rax = Regs->Rax;
+  GhcbSetRegValid (Ghcb, GhcbRax);
+  Ghcb->SaveArea.Cpl = (UINT8) (Regs->Cs & 0x3);
+  GhcbSetRegValid (Ghcb, GhcbCpl);
+
+  Status = VmgExit (Ghcb, SVM_EXIT_VMMCALL, 0, 0);
+  if (Status) {

(1) Please write (Status > 0) or (Status != 0).

Acked-by: Laszlo Ersek <ler...@redhat.com>

Thanks
Laszlo

+    return Status;
+  }
+
+  if (!GhcbIsRegValid (Ghcb, GhcbRax)) {
+    return UnsupportedExit (Ghcb, Regs, InstructionData);
+  }
+  Regs->Rax = Ghcb->SaveArea.Rax;
+
+  return 0;
+}
+
  /**
    Handle an MSR event.
@@ -1395,6 +1439,10 @@ VmgExitHandleVc (
      NaeExit = MsrExit;
      break;
+ case SVM_EXIT_VMMCALL:
+    NaeExit = VmmCallExit;
+    break;
+
    case SVM_EXIT_WBINVD:
      NaeExit = WbinvdExit;
      break;







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