On 09/04/2017 10:57 AM, Laszlo Ersek wrote:
In commit b6d11d7c4678 ("MdePkg: BaseIoLibIntrinsic (IoLib class)
library", 2017-04-12), the MOV instructions in the write loops were
probably copied from the read loops. However, the operand order was not
adjusted.
As a result, the IoWriteFifoXX() routines, when invoked in SEV guests, now
overwrite the source buffer with value 0x01 / 0x0001 / 0x00000001 -- the
SevNoRepIo() function returns value 1 in EAX, in SEV guests --, and write
the same value to the target IO port.
Fix this by putting the target operand (AL / AX / EAX) first, and the
source operand (BYTE / WORD / DWORD [ESI/RSI]) second.
Cc: Brijesh Singh <[email protected]>
Cc: Jordan Justen <[email protected]>
Cc: Liming Gao <[email protected]>
Cc: Michael D Kinney <[email protected]>
Fixes: b6d11d7c467810ea7f2e2eda46ef0bdc57bf1475
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <[email protected]>
Reviewed-by: Brijesh Singh <[email protected]>
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