[PATCH v6 3/6] OvmfPkg/BaseMemEncryptLib: Invoke page encryption state change hypercall


Ashish Kalra
 

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

Invoke the hypercall API to notify hypervisor when the page's
encryption state changes.

Cc: Jordan Justen <jordan.l.justen@...>
Cc: Ard Biesheuvel <ard.biesheuvel@...>
Signed-off-by: Brijesh Singh <brijesh.singh@...>
Signed-off-by: Ashish Kalra <ashish.kalra@...>
---
OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index c696745f9d..f562e16fc2 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -585,6 +585,9 @@ SetMemoryEncDec (
UINT64 AddressEncMask;
BOOLEAN IsWpEnabled;
RETURN_STATUS Status;
+ UINTN Size;
+ BOOLEAN CBitChanged;
+ PHYSICAL_ADDRESS OrigPhysicalAddress;

//
// Set PageMapLevel4Entry to suppress incorrect compiler/analyzer warnings.
@@ -636,6 +639,9 @@ SetMemoryEncDec (

Status = EFI_SUCCESS;

+ Size = Length;
+ CBitChanged = FALSE;
+ OrigPhysicalAddress = PhysicalAddress;
while (Length != 0)
{
//
@@ -695,6 +701,7 @@ SetMemoryEncDec (
));
PhysicalAddress += BIT30;
Length -= BIT30;
+ CBitChanged = TRUE;
} else {
//
// We must split the page
@@ -749,6 +756,7 @@ SetMemoryEncDec (
SetOrClearCBit (&PageDirectory2MEntry->Uint64, Mode);
PhysicalAddress += BIT21;
Length -= BIT21;
+ CBitChanged = TRUE;
} else {
//
// We must split up this page into 4K pages
@@ -791,6 +799,7 @@ SetMemoryEncDec (
SetOrClearCBit (&PageTableEntry->Uint64, Mode);
PhysicalAddress += EFI_PAGE_SIZE;
Length -= EFI_PAGE_SIZE;
+ CBitChanged = TRUE;
}
}
}
@@ -808,6 +817,17 @@ SetMemoryEncDec (
//
CpuFlushTlb();

+ //
+ // Notify Hypervisor on C-bit status
+ //
+ if (CBitChanged) {
+ Status = SetMemoryEncDecHypercall3 (
+ OrigPhysicalAddress,
+ EFI_SIZE_TO_PAGES(Size),
+ (Mode == SetCBit) ? TRUE : FALSE
+ );
+ }
+
Done:
//
// Restore page table write protection, if any.
--
2.17.1

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