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KVM: SEV-ES: Disallow SEV-ES guests when X86_FEATURE_LBRV is absent

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As documented in APM[1], LBR Virtualization must be enabled for SEV-ES
guests. So, prevent SEV-ES guests when LBRV support is missing.

[1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June
     2023, Vol 2, 15.35.2 Enabling SEV-ES.
     https://bugzilla.kernel.org/attachment.cgi?id=304653

Fixes: 376c6d285017 ("KVM: SVM: Provide support for SEV-ES vCPU creation/loading")
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Message-ID: <20240531044644.768-3-ravi.bangoria@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ravi Bangoria 2024-05-31 04:46:43 +00:00 committed by Paolo Bonzini
parent 27bd5fdc24
commit d922056215
3 changed files with 14 additions and 9 deletions
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6
arch/x86/kvm/svm/sev.c
View File

@ -2406,6 +2406,12 @@ void __init sev_hardware_setup(void)
if (!boot_cpu_has(X86_FEATURE_SEV_ES))
goto out;
if (!lbrv) {
WARN_ONCE(!boot_cpu_has(X86_FEATURE_LBRV),
"LBRV must be present for SEV-ES support");
goto out;
}
/* Has the system been allocated ASIDs for SEV-ES? */
if (min_sev_asid == 1)
goto out;

16
arch/x86/kvm/svm/svm.c
View File

@ -215,7 +215,7 @@ int vgif = true;
module_param(vgif, int, 0444);
/* enable/disable LBR virtualization */
static int lbrv = true;
int lbrv = true;
module_param(lbrv, int, 0444);
static int tsc_scaling = true;
@ -5294,6 +5294,12 @@ static __init int svm_hardware_setup(void)
nrips = nrips && boot_cpu_has(X86_FEATURE_NRIPS);
if (lbrv) {
if (!boot_cpu_has(X86_FEATURE_LBRV))
lbrv = false;
else
pr_info("LBR virtualization supported\n");
}
/*
* Note, SEV setup consumes npt_enabled and enable_mmio_caching (which
* may be modified by svm_adjust_mmio_mask()), as well as nrips.
@ -5347,14 +5353,6 @@ static __init int svm_hardware_setup(void)
svm_x86_ops.set_vnmi_pending = NULL;
}
if (lbrv) {
if (!boot_cpu_has(X86_FEATURE_LBRV))
lbrv = false;
else
pr_info("LBR virtualization supported\n");
}
if (!enable_pmu)
pr_info("PMU virtualization is disabled\n");

1
arch/x86/kvm/svm/svm.h
View File

@ -39,6 +39,7 @@ extern int vgif;
extern bool intercept_smi;
extern bool x2avic_enabled;
extern bool vnmi;
extern int lbrv;
/*
* Clean bits in VMCB.