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Fix multiple bugs, refactor InitializeMsrBitmaps

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This commit is contained in:
Satoshi Tanda
2020-03-08 20:12:24 -07:00
parent d19ea35db2
commit b49a595b0a
6 changed files with 139 additions and 18 deletions
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12
Sources/Asm.asm
View File

@@ -123,12 +123,12 @@ AsmHypervisorEntryPoint proc frame
;
; Restore XMM registers.
;
movaps xmm0, xmmword ptr [rsp + 0h]
movaps xmm1, xmmword ptr [rsp + 10h]
movaps xmm2, xmmword ptr [rsp + 20h]
movaps xmm3, xmmword ptr [rsp + 30h]
movaps xmm4, xmmword ptr [rsp + 40h]
movaps xmm5, xmmword ptr [rsp + 50h]
movaps xmm4, xmmword ptr [rsp + 40h]
movaps xmm3, xmmword ptr [rsp + 30h]
movaps xmm2, xmmword ptr [rsp + 20h]
movaps xmm1, xmmword ptr [rsp + 10h]
movaps xmm0, xmmword ptr [rsp + 0h]
add rsp, 68h
;
@@ -182,7 +182,7 @@ VmxError:
; VMRESUME or VMXOFF instruction failed. Unrecoverble. The most useful
; thing to do here is to call a C-function to diagnose the issue.
;
pushf
pushfq
PUSHAQ
mov rcx, rsp
sub rsp, 20h

95
Sources/HostUtils.c
View File

@@ -421,13 +421,16 @@ FindImageBase (
UINT64 GuestVirtualAddress
)
{
UINT64 imageBase;
//
// Starting with the 1MB aligned address, and search up IMAGE_DOS_SIGNATURE
// every 1MB.
// Starting with the page aligned address, and search up IMAGE_DOS_SIGNATURE
// every page up to 16MB (0x1000000). Ntoskrnl.exe can be mapped at the page
// boundary and not the 64KB boundary unlike other images.
//
for (UINT64 imageBase = (GuestVirtualAddress & ~(0x10000 - 1));
/**/;
imageBase -= 0x10000)
imageBase = (GuestVirtualAddress & ~(PAGE_SIZE - 1));
for (int i = 0; i < 0x1000; i++, imageBase -= PAGE_SIZE)
{
BOOLEAN ok;
UINT16 contents;
@@ -441,12 +444,90 @@ FindImageBase (
&errorInfo);
if (ok == FALSE)
{
return 0;
continue;
}
if (contents == 0x5A4D)
{
return imageBase;
goto Exit;
}
}
imageBase = 0;
Exit:
return imageBase;
}
_Use_decl_annotations_
VOID
UpdateMsrBitmaps (
MSR_BITMAPS* Bitmaps,
IA32_MSR_ADDRESS Msr,
OPERATION_TYPE InterOperation,
BOOLEAN Intercept
)
{
IA32_MSR_ADDRESS msrTemp;
BOOLEAN highValue;
UINT64 byteOffset;
UINT64 bitMask;
UINT8* msrBitmap;
//
// MSR must be within either 0x0 - 0x1fff or 0xc0000000 - 0xc0001fff
// inclusive, and at least read or write intercept must be specified.
//
MV_ASSERT((Msr <= 0x1fff) ||
((Msr >= 0xc0000000) && (Msr <= 0xc0001fff)));
//
// Check if the MSR belongs to high bitmaps.
//
highValue = BooleanFlagOn(Msr, 0xc0000000);
//
// Computes offsets and bitmaps to update the bitmaps.
//
msrTemp = (Msr & ~0xc0000000);
byteOffset = (msrTemp / CHAR_BIT);
bitMask = (1ull << (msrTemp % CHAR_BIT));
//
// Select the bitmap to work on.
//
if (InterOperation == OperationRead)
{
if (highValue == FALSE)
{
msrBitmap = Bitmaps->ReadBitmapLow;
}
else
{
msrBitmap = Bitmaps->ReadBitmapHigh;
}
}
else
{
if (highValue == FALSE)
{
msrBitmap = Bitmaps->WriteBitmapLow;
}
else
{
msrBitmap = Bitmaps->WriteBitmapHigh;
}
}
//
// Set of clear the bit.
//
if (Intercept != FALSE)
{
SetFlag(msrBitmap[byteOffset], bitMask);
}
else
{
ClearFlag(msrBitmap[byteOffset], bitMask);
}
}

21
Sources/HostUtils.h
View File

@@ -231,3 +231,24 @@ FindImageBase (
_In_ GUEST_CONTEXT* GuestContext,
_In_ UINT64 GuestVirtualAddress
);
/*!
@brief Updates the MSR bitmap as specified.
@param[in] Bitmaps - The pointer to the MSR bitmaps.
@param[in,out] Msr - The MSR to change configurations. Must be in the range of
0x0 - 0x1fff or 0xc0000000 - 0xc0001fff.
@param[in] InterOperation - The type of operation to change configurations.
@param[in] Intercept - TRUE if the hypervisor should intercept the specified
type of access.
*/
VOID
UpdateMsrBitmaps (
_Inout_ MSR_BITMAPS* Bitmaps,
_In_ IA32_MSR_ADDRESS Msr,
_In_ OPERATION_TYPE InterOperation,
_In_ BOOLEAN Intercept
);

2
Sources/HostVmcall.c
View File

@@ -43,7 +43,7 @@ HandleVmcallUninstall (
//
gdtr.BaseAddress = VmxRead(VMCS_GUEST_GDTR_BASE);
gdtr.Limit = (UINT16)VmxRead(VMCS_GUEST_GDTR_LIMIT);
_sgdt(&gdtr);
_lgdt(&gdtr);
idtr.BaseAddress = VmxRead(VMCS_GUEST_IDTR_BASE);
idtr.Limit = (UINT16)VmxRead(VMCS_GUEST_IDTR_LIMIT);

21
Sources/MiniVisor.c
View File

@@ -996,6 +996,7 @@ SetupVmcs (
// Finally, place necessary data for hypervisor into the hypervisor stack.
//
ProcessorContext->HypervisorStack.u.Layout.Context.ProcessorNumber = GetCurrentProcessorNumber();
ProcessorContext->HypervisorStack.u.Layout.Context.SharedMsrBitmaps = &SharedProcessorContext->MsrBitmaps;
ProcessorContext->HypervisorStack.u.Layout.Context.SharedProcessorContext = SharedProcessorContext;
ProcessorContext->HypervisorStack.u.Layout.Context.EptContext = &ProcessorContext->EptContext;
ProcessorContext->HypervisorStack.u.Layout.Context.MemoryAccessContext = &ProcessorContext->MemoryAccessContext;
@@ -1178,14 +1179,28 @@ 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));
typedef struct _INTERCEPT_MSR_REGISTRATION
{
IA32_MSR_ADDRESS Msr;
OPERATION_TYPE InterceptType;
} INTERCEPT_MSR_REGISTRATION;
static CONST INTERCEPT_MSR_REGISTRATION registrations[] =
{
{ IA32_BIOS_SIGN_ID, OperationRead, },
};
PAGED_CODE();
RtlZeroMemory(Bitmaps, sizeof(*Bitmaps));
Bitmaps->ReadBitmapLow[biosSignatureByteOffset] |= biosSignatureBitMask;
for (int i = 0; i < RTL_NUMBER_OF(registrations); ++i)
{
UpdateMsrBitmaps(Bitmaps,
registrations[i].Msr,
registrations[i].InterceptType,
TRUE);
}
}
/*!

6
Sources/Public.h
View File

@@ -41,7 +41,11 @@ typedef struct _HYPERVISOR_CONTEXT
//
UINT32 ProcessorNumber;
UINT32 Padding1;
UINT64 Padding2;
//
// The pointer to the MSR bitmaps that are shared across processor.
//
struct _MSR_BITMAPS* SharedMsrBitmaps;
//
// A pointer to the shared processor context. This value is not used by the