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43 lines
1.7 KiB
43 lines
1.7 KiB
1 year ago
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From bcc2e81950016f6cda6f3c125bfa7c88a5f8ca8e Mon Sep 17 00:00:00 2001
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From: Tom Lendacky <thomas.lendacky@amd.com>
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Date: Fri, 14 Jul 2023 15:28:26 -0500
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Subject: [PATCH] OvmfPkg/ResetVector: Fix assembler bit test flag check
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RH-Author: Gerd Hoffmann <None>
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RH-MergeRequest: 47: OvmfPkg/ResetVector: Fix assembler bit test flag check
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RH-Jira: RHEL-9943
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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RH-Commit: [1/1] 4565e2863391eb63d598991bc1b394cabd96a466 (kraxel.rh/centos-src-edk2)
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Commit 63c50d3ff2854a76432b752af4f2a76f33ff1974 changed the check that is
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used to determine if SEV-ES is active. Originally, a CMP instruction with
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a supporting JZ instruction was used for the check. It was changed to use
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the BT instruction but not JZ instruction. The result of a BT instruction
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changes the the carry flag (CF) and not the zero flag (ZF). As a result,
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the wrong condition is being checked. Update the JZ to a JNC to properly
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detect if SEV-ES is active.
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Fixes: 63c50d3ff285 ("OvmfPkg/ResetVector: cache the SEV status MSR...")
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Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
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(cherry picked from commit e674096accc8e57cd0dd84679905e1222423251e)
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---
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OvmfPkg/ResetVector/Ia32/Flat32ToFlat64.asm | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/OvmfPkg/ResetVector/Ia32/Flat32ToFlat64.asm b/OvmfPkg/ResetVector/Ia32/Flat32ToFlat64.asm
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index c5c683ebed..429a58c5ef 100644
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--- a/OvmfPkg/ResetVector/Ia32/Flat32ToFlat64.asm
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+++ b/OvmfPkg/ResetVector/Ia32/Flat32ToFlat64.asm
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@@ -44,7 +44,7 @@ Transition32FlatTo64Flat:
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mov ecx, 1
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bt [SEV_ES_WORK_AREA_STATUS_MSR], ecx
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- jz EnablePaging
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+ jnc EnablePaging
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;
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; SEV-ES is active, perform a quick sanity check against the reported
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--
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2.39.3
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