58 lines
2.4 KiB
Diff
58 lines
2.4 KiB
Diff
From 522ce31b4998b714b03e781f49403b71531ebe5a Mon Sep 17 00:00:00 2001
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From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>
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Date: Mon, 23 May 2022 18:26:58 +0200
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Subject: [PATCH 5/5] target/i386/kvm: Fix disabling MPX on "-cpu host" with
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MPX-capable host
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RH-Author: Ani Sinha <None>
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RH-MergeRequest: 297: target/i386/kvm: Fix disabling MPX on "-cpu host" with MPX-capable host
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RH-Bugzilla: 2223947
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RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>
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RH-Acked-by: Jon Maloy <jmaloy@redhat.com>
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RH-Commit: [1/1] 90098294a873a53b366389606fd0402efcbd70ad
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Since KVM commit 5f76f6f5ff96 ("KVM: nVMX: Do not expose MPX VMX controls when guest MPX disabled")
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it is not possible to disable MPX on a "-cpu host" just by adding "-mpx"
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there if the host CPU does indeed support MPX.
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QEMU will fail to set MSR_IA32_VMX_TRUE_{EXIT,ENTRY}_CTLS MSRs in this case
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and so trigger an assertion failure.
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Instead, besides "-mpx" one has to explicitly add also
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"-vmx-exit-clear-bndcfgs" and "-vmx-entry-load-bndcfgs" to QEMU command
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line to make it work, which is a bit convoluted.
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Make the MPX-related bits in FEAT_VMX_{EXIT,ENTRY}_CTLS dependent on MPX
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being actually enabled so such workarounds are no longer necessary.
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Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
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Message-Id: <51aa2125c76363204cc23c27165e778097c33f0b.1653323077.git.maciej.szmigiero@oracle.com>
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Cc: qemu-stable@nongnu.org
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 267b5e7e378afd260004cb37a66a6fcd641e3b53)
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---
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target/i386/cpu.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/target/i386/cpu.c b/target/i386/cpu.c
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index 265f0aadfc..726814ee2e 100644
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--- a/target/i386/cpu.c
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+++ b/target/i386/cpu.c
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@@ -1326,6 +1326,14 @@ static FeatureDep feature_dependencies[] = {
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.from = { FEAT_7_0_EBX, CPUID_7_0_EBX_INVPCID },
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.to = { FEAT_VMX_SECONDARY_CTLS, VMX_SECONDARY_EXEC_ENABLE_INVPCID },
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},
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+ {
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+ .from = { FEAT_7_0_EBX, CPUID_7_0_EBX_MPX },
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+ .to = { FEAT_VMX_EXIT_CTLS, VMX_VM_EXIT_CLEAR_BNDCFGS },
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+ },
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+ {
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+ .from = { FEAT_7_0_EBX, CPUID_7_0_EBX_MPX },
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+ .to = { FEAT_VMX_ENTRY_CTLS, VMX_VM_ENTRY_LOAD_BNDCFGS },
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+ },
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{
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.from = { FEAT_7_0_EBX, CPUID_7_0_EBX_RDSEED },
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.to = { FEAT_VMX_SECONDARY_CTLS, VMX_SECONDARY_EXEC_RDSEED_EXITING },
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--
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2.37.3
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