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Message-ID: <20200527012039.GC31696@linux.intel.com>
Date: Tue, 26 May 2020 18:20:39 -0700
From: Sean Christopherson <sean.j.christopherson@...el.com>
To: Maxim Levitsky <mlevitsk@...hat.com>
Cc: kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, Tao Xu <tao3.xu@...el.com>,
Jim Mattson <jmattson@...gle.com>,
linux-kernel@...r.kernel.org, Joerg Roedel <joro@...tes.org>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
Wanpeng Li <wanpengli@...cent.com>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...en8.de>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Jingqi Liu <jingqi.liu@...el.com>
Subject: Re: [PATCH 1/2] kvm/x86/vmx: enable X86_FEATURE_WAITPKG in KVM
capabilities
On Sat, May 23, 2020 at 07:14:54PM +0300, Maxim Levitsky wrote:
> Even though we might not allow the guest to use
> WAITPKG's new instructions, we should tell KVM
> that the feature is supported by the host CPU.
>
> Note that vmx_waitpkg_supported checks that WAITPKG
> _can_ be set in secondary execution controls as specified
> by VMX capability MSR, rather that we actually enable it for a guest.
These line wraps are quite weird and inconsistent.
>
> Fixes: e69e72faa3a0 KVM: x86: Add support for user wait instructions
Checkpatch doesn't complain, but the preferred Fixes format is
Fixes: e69e72faa3a07 ("KVM: x86: Add support for user wait instructions")
e.g.
git show -s --pretty='tformat:%h ("%s")'
For the code itself:
Reviewed-by: Sean Christopherson <sean.j.christopherson@...el.com>
> Suggested-by: Paolo Bonzini <pbonzini@...hat.com>
> Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
> ---
> arch/x86/kvm/vmx/vmx.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 55712dd86bafa..fca493d4517c5 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -7298,6 +7298,9 @@ static __init void vmx_set_cpu_caps(void)
> /* CPUID 0x80000001 */
> if (!cpu_has_vmx_rdtscp())
> kvm_cpu_cap_clear(X86_FEATURE_RDTSCP);
> +
> + if (vmx_waitpkg_supported())
> + kvm_cpu_cap_check_and_set(X86_FEATURE_WAITPKG);
> }
>
> static void vmx_request_immediate_exit(struct kvm_vcpu *vcpu)
> --
> 2.26.2
>
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