admin/MiniVisorPkg
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Emulate IA32_BIOS_SIGN_ID read

Browse Source
This commit is contained in:
Satoshi Tanda
2020-02-23 13:12:33 -08:00
parent b9b638d32b
commit fa47889170
4 changed files with 89 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
Sources/MiniVisor.c
View File

@@ -149,19 +149,9 @@ typedef struct _SHARED_PROCESSOR_CONTEXT
UINT32 NumberOfContexts;
//
// The page-aligned, 4KB size region used as a MSR bitmap. The MSR bitmap is
// used to indicate which MSR should cause VM-exit on RDMSR and WRMSR. Each
// bit in this 4KB region represents ON or OFF of VM-exit, where 0 indicates
// not to trigger, and 1 indicates to trigger VM-exit. This hypervisor does
// not intend to handle MSR accesses and so, all bits are left as 0. It is
// important that this bitmap governs VM-exit behavior only for certain sets
// of MSRs. An access to any MSR that is not governed by this bitmap still
// causes VM-exit unconditionally. For this reason, this hypervisor still
// has RDMSR and WRMSR handling logic.
// The MSR bitmap used across all processors.
//
// See: 24.6.9 MSR-Bitmap Address
//
DECLSPEC_ALIGN(PAGE_SIZE) VOID* MsrBitmap;
DECLSPEC_ALIGN(PAGE_SIZE) MSR_BITMAPS MsrBitmaps;
//
// An array of PER_PROCESSOR_CONTEXTs. Each context is associated with and
@@ -918,7 +908,7 @@ SetupVmcs (
VmxWrite(VMCS_CTRL_VIRTUAL_PROCESSOR_IDENTIFIER, 1);
/* 64-Bit Control Fields */
VmxWrite(VMCS_CTRL_MSR_BITMAP_ADDRESS, GetPhysicalAddress(&VpContexts->MsrBitmap));
VmxWrite(VMCS_CTRL_MSR_BITMAP_ADDRESS, GetPhysicalAddress(&VpContexts->MsrBitmaps));
VmxWrite(VMCS_CTRL_EPT_POINTER, VpContext->EptContext.EptPointer.Flags);
/* 32-Bit Control Fields */
@@ -1165,9 +1155,36 @@ Exit:
}
/*!
@brief Enables hypervisor on the all processors.
@brief Initializes the MSR bitmaps.
@return MV_STATUS_SUCCESS on success; otherwise, an appropriate error code.
@details This function clears the bitmaps to avoid VM-exits that do not require
manual handling. The MSR that requires manual handling for MiniVisor is
IA32_BIOS_SIGN_ID to prevent the guest from attempting update BIOS
microcode. See HandleMsrAccess for more details.
@param[out] Bitmaps - The pointer to the MSR bitmaps to initialize.
*/
MV_SECTION_PAGED
static
VOID
InitializeMsrBitmaps (
_Out_ MSR_BITMAPS* Bitmaps
)
{
static CONST UINT64 biosSignatureByteOffset = (IA32_BIOS_SIGN_ID / CHAR_BIT);
static CONST UINT64 biosSignatureBitMask = (1ull << (IA32_BIOS_SIGN_ID % CHAR_BIT));
PAGED_CODE()
RtlZeroMemory(Bitmaps, sizeof(*Bitmaps));
Bitmaps->ReadBitmapLow[biosSignatureByteOffset] |= biosSignatureBitMask;
}
/*!
@brief Enables hypervisor on the all processors.
@return MV_STATUS_SUCCESS on success; otherwise, an appropriate error code.
*/
MV_SECTION_PAGED
static
@@ -1211,6 +1228,7 @@ EnableHypervisorOnAllProcessors (
goto Exit;
}
vpContexts->NumberOfContexts = numberOfProcessors;
InitializeMsrBitmaps(&vpContexts->MsrBitmaps);
//
// Start virtualizing processors one-by-one. This is done by changing