Re: [PATCH v2 09/13] OvmfPkg/BaseMemEncryptSevLib: introduce MemEncryptSevClearMmioPageEncMask()


Laszlo Ersek
 

On 05/13/21 01:46, Brijesh Singh wrote:
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

The MemEncryptSevClearMmioPageEncMask() helper can be used for clearing
the memory encryption mask for the Mmio region.

The MemEncryptSevClearMmioPageEncMask() is a simplified version of
MemEncryptSevClearPageEncMask() -- it does not flush the caches after
clearing the page encryption mask.

Cc: James Bottomley <jejb@...>
Cc: Min Xu <min.m.xu@...>
Cc: Jiewen Yao <jiewen.yao@...>
Cc: Tom Lendacky <thomas.lendacky@...>
Cc: Jordan Justen <jordan.l.justen@...>
Cc: Ard Biesheuvel <ardb+tianocore@...>
Cc: Laszlo Ersek <lersek@...>
Cc: Erdem Aktas <erdemaktas@...>
Reviewed-by: Laszlo Ersek <lersek@...>
Signed-off-by: Brijesh Singh <brijesh.singh@...>
---
OvmfPkg/Include/Library/MemEncryptSevLib.h | 25 ++++++++++++++
.../BaseMemEncryptSevLib/X64/VirtualMemory.h | 23 +++++++++++++
.../Ia32/MemEncryptSevLib.c | 31 +++++++++++++++++
.../X64/MemEncryptSevLib.c | 33 +++++++++++++++++++
.../X64/PeiDxeVirtualMemory.c | 33 +++++++++++++++++++
.../X64/SecVirtualMemory.c | 30 +++++++++++++++++
6 files changed, 175 insertions(+)
Sorry that I missed last time that the "SecMemEncryptSevLib.inf"
instance was not extended with a definition for the new function.

This update looks OK; my R-b stands.

Thanks
Laszlo


diff --git a/OvmfPkg/Include/Library/MemEncryptSevLib.h b/OvmfPkg/Include/Library/MemEncryptSevLib.h
index 99f15a7d1271..b91490d5d44d 100644
--- a/OvmfPkg/Include/Library/MemEncryptSevLib.h
+++ b/OvmfPkg/Include/Library/MemEncryptSevLib.h
@@ -203,4 +203,29 @@ MemEncryptSevGetAddressRangeState (
IN UINTN Length
);

+/**
+ This function clears memory encryption bit for the MMIO region specified by
+ BaseAddress and NumPages.
+
+ @param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
+ current CR3)
+ @param[in] BaseAddress The physical address that is the start
+ address of a MMIO region.
+ @param[in] NumPages The number of pages from start memory
+ region.
+
+ @retval RETURN_SUCCESS The attributes were cleared for the
+ memory region.
+ @retval RETURN_INVALID_PARAMETER Number of pages is zero.
+ @retval RETURN_UNSUPPORTED Clearing the memory encryption attribute
+ is not supported
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevClearMmioPageEncMask (
+ IN PHYSICAL_ADDRESS Cr3BaseAddress,
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ );
+
#endif // _MEM_ENCRYPT_SEV_LIB_H_
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
index fe2a0b2826cd..8dc39e647b90 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
@@ -126,4 +126,27 @@ InternalMemEncryptSevGetAddressRangeState (
IN UINTN Length
);

+/**
+ This function clears memory encryption bit for the MMIO region specified by
+ PhysicalAddress and Length.
+
+ @param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
+ current CR3)
+ @param[in] PhysicalAddress The physical address that is the start
+ address of a MMIO region.
+ @param[in] Length The length of memory region
+
+ @retval RETURN_SUCCESS The attributes were cleared for the
+ memory region.
+ @retval RETURN_INVALID_PARAMETER Length is zero.
+ @retval RETURN_UNSUPPORTED Clearing the memory encyrption attribute
+ is not supported
+**/
+RETURN_STATUS
+EFIAPI
+InternalMemEncryptSevClearMmioPageEncMask (
+ IN PHYSICAL_ADDRESS Cr3BaseAddress,
+ IN PHYSICAL_ADDRESS PhysicalAddress,
+ IN UINTN Length
+ );
#endif
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
index 12a5bf495bd7..169d3118e44f 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
@@ -111,3 +111,34 @@ MemEncryptSevGetAddressRangeState (
//
return MemEncryptSevAddressRangeEncrypted;
}
+
+/**
+ This function clears memory encryption bit for the MMIO region specified by
+ BaseAddress and NumPages.
+
+ @param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
+ current CR3)
+ @param[in] BaseAddress The physical address that is the start
+ address of a MMIO region.
+ @param[in] NumPages The number of pages from start memory
+ region.
+
+ @retval RETURN_SUCCESS The attributes were cleared for the
+ memory region.
+ @retval RETURN_INVALID_PARAMETER Number of pages is zero.
+ @retval RETURN_UNSUPPORTED Clearing the memory encryption attribute
+ is not supported
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevClearMmioPageEncMask (
+ IN PHYSICAL_ADDRESS Cr3BaseAddress,
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ )
+{
+ //
+ // Memory encryption bit is not accessible in 32-bit mode
+ //
+ return RETURN_UNSUPPORTED;
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
index 4fea6a6be0ac..a2bf698bcde7 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
@@ -118,3 +118,36 @@ MemEncryptSevGetAddressRangeState (
Length
);
}
+
+/**
+ This function clears memory encryption bit for the mmio region specified by
+ BaseAddress and NumPages.
+
+ @param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
+ current CR3)
+ @param[in] BaseAddress The physical address that is the start
+ address of a mmio region.
+ @param[in] NumPages The number of pages from start memory
+ region.
+
+ @retval RETURN_SUCCESS The attributes were cleared for the
+ memory region.
+ @retval RETURN_INVALID_PARAMETER Number of pages is zero.
+ @retval RETURN_UNSUPPORTED Clearing the memory encryption attribute
+ is not supported
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevClearMmioPageEncMask (
+ IN PHYSICAL_ADDRESS Cr3BaseAddress,
+ IN PHYSICAL_ADDRESS BaseAddress,
+ IN UINTN NumPages
+ )
+{
+ return InternalMemEncryptSevClearMmioPageEncMask (
+ Cr3BaseAddress,
+ BaseAddress,
+ EFI_PAGES_TO_SIZE (NumPages)
+ );
+
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index d3455e812bd1..a18d336a8789 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -891,3 +891,36 @@ InternalMemEncryptSevSetMemoryEncrypted (
Flush
);
}
+
+/**
+ This function clears memory encryption bit for the MMIO region specified by
+ PhysicalAddress and Length.
+
+ @param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
+ current CR3)
+ @param[in] PhysicalAddress The physical address that is the start
+ address of a MMIO region.
+ @param[in] Length The length of memory region
+
+ @retval RETURN_SUCCESS The attributes were cleared for the
+ memory region.
+ @retval RETURN_INVALID_PARAMETER Length is zero.
+ @retval RETURN_UNSUPPORTED Clearing the memory encyrption attribute
+ is not supported
+**/
+RETURN_STATUS
+EFIAPI
+InternalMemEncryptSevClearMmioPageEncMask (
+ IN PHYSICAL_ADDRESS Cr3BaseAddress,
+ IN PHYSICAL_ADDRESS PhysicalAddress,
+ IN UINTN Length
+ )
+{
+ return SetMemoryEncDec (
+ Cr3BaseAddress,
+ PhysicalAddress,
+ Length,
+ ClearCBit,
+ FALSE
+ );
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
index bca5e3febb1b..e0d3a15e8503 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
@@ -98,3 +98,33 @@ InternalMemEncryptSevSetMemoryEncrypted (
//
return RETURN_UNSUPPORTED;
}
+
+/**
+ This function clears memory encryption bit for the MMIO region specified by
+ PhysicalAddress and Length.
+
+ @param[in] Cr3BaseAddress Cr3 Base Address (if zero then use
+ current CR3)
+ @param[in] PhysicalAddress The physical address that is the start
+ address of a MMIO region.
+ @param[in] Length The length of memory region
+
+ @retval RETURN_SUCCESS The attributes were cleared for the
+ memory region.
+ @retval RETURN_INVALID_PARAMETER Length is zero.
+ @retval RETURN_UNSUPPORTED Clearing the memory encyrption attribute
+ is not supported
+**/
+RETURN_STATUS
+EFIAPI
+InternalMemEncryptSevClearMmioPageEncMask (
+ IN PHYSICAL_ADDRESS Cr3BaseAddress,
+ IN PHYSICAL_ADDRESS PhysicalAddress,
+ IN UINTN Length
+ )
+{
+ //
+ // This function is not available during SEC.
+ //
+ return RETURN_UNSUPPORTED;
+}

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