[PATCH v8 4/6] OvmfPkg/VmgExitLib: Encryption state change hypercall support in VC handler

["Ashish Kalra" <ashish.kalra@amd.com>]

From: Ashish Kalra <ashish.kalra@amd.com>

Make the #VC handler aware of the page encryption state
change hypercall by adding support to check KVM_HC_MAP_GPA_RANGE
hypercall and add the additional register values used by
hypercall in the GHCB.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
index a4393dffbd..ee213ae2cb 100644
--- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
+++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
@@ -1211,6 +1211,19 @@ VmmCallExit (
   Ghcb->SaveArea.Cpl = (UINT8)(Regs->Cs & 0x3);
   VmgSetOffsetValid (Ghcb, GhcbCpl);
 
+  if (Regs->Rax == KVM_HC_MAP_GPA_RANGE) {
+    //
+    // KVM_HC_MAP_GPA_RANGE hypercall requires these
+    // extra registers.
+    //
+    Ghcb->SaveArea.Rbx = Regs->Rbx;
+    VmgSetOffsetValid (Ghcb, GhcbRbx);
+    Ghcb->SaveArea.Rcx = Regs->Rcx;
+    VmgSetOffsetValid (Ghcb, GhcbRcx);
+    Ghcb->SaveArea.Rdx = Regs->Rdx;
+    VmgSetOffsetValid (Ghcb, GhcbRdx);
+  }
+
   Status = VmgExit (Ghcb, SVM_EXIT_VMMCALL, 0, 0);
   if (Status != 0) {
     return Status;
-- 
2.25.1