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    SubjectRe: [PATCH] KVM: x86: Set BHI_NO in guest when host is not affected by BHI
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    On 11.04.24 г. 10:24 ч., Alexandre Chartre wrote:
    > When a system is not affected by the BHI bug then KVM should
    > configure guests with BHI_NO to ensure they won't enable any
    > BHI mitigation.
    >
    > Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
    > ---
    > arch/x86/kvm/x86.c | 3 +++
    > 1 file changed, 3 insertions(+)
    >
    > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
    > index 984ea2089efc..f43d3c15a6b7 100644
    > --- a/arch/x86/kvm/x86.c
    > +++ b/arch/x86/kvm/x86.c
    > @@ -1678,6 +1678,9 @@ static u64 kvm_get_arch_capabilities(void)
    > if (!boot_cpu_has_bug(X86_BUG_GDS) || gds_ucode_mitigated())
    > data |= ARCH_CAP_GDS_NO;
    >
    > + if (!boot_cpu_has_bug(X86_BUG_BHI))
    > + data |= ARCH_CAP_BHI_NO;
    > +

    But this is already handled since ARCH_CAP_BHI_NO is added to
    KVM_SUPPORTED_ARCH_CAP so when the host caps are read that bit is going
    to be set there, if it's set for the physical cpu of course.
    > return data;
    > }
    >

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