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From: Sean Christopherson <seanjc@google.com>
To: Michael Roth <michael.roth@amd.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
	linux-kernel@vger.kernel.org,
	Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH v4 1/3] KVM: SVM: use vmsave/vmload for saving/restoring additional host state
Date: Tue, 2 Feb 2021 16:38:02 -0800	[thread overview]
Message-ID: <YBnwaiy8L/O0PCrR@google.com> (raw)
In-Reply-To: <20210202190126.2185715-2-michael.roth@amd.com>

One quick comment while it's on my mind, I'll give this a proper gander tomorrow.

On Tue, Feb 02, 2021, Michael Roth wrote:
> diff --git a/arch/x86/kvm/svm/svm_ops.h b/arch/x86/kvm/svm/svm_ops.h
> index 0c8377aee52c..c2a05f56c8e4 100644
> --- a/arch/x86/kvm/svm/svm_ops.h
> +++ b/arch/x86/kvm/svm/svm_ops.h
> @@ -56,4 +56,9 @@ static inline void vmsave(hpa_t pa)
>  	svm_asm1(vmsave, "a" (pa), "memory");
>  }
>  
> +static inline void vmload(hpa_t pa)

This needs to be 'unsigned long', using 'hpa_t' in vmsave() is wrong as the
instructions consume rAX based on effective address.  I wrote the function
comment for the vmsave() fix so that it applies to both VMSAVE and VMLOAD,
so this can be a simple fixup on application (assuming v5 isn't needed for
other reasons).

https://lkml.kernel.org/r/20210202223416.2702336-1-seanjc@google.com

> +{
> +	svm_asm1(vmload, "a" (pa), "memory");
> +}
> +
>  #endif /* __KVM_X86_SVM_OPS_H */
> -- 
> 2.25.1
> 

  reply	other threads:[~2021-02-03  0:39 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02 19:01 [PATCH v4 0/3] KVM: SVM: Refactor vcpu_load/put to use vmload/vmsave for host state Michael Roth
2021-02-02 19:01 ` [PATCH v4 1/3] KVM: SVM: use vmsave/vmload for saving/restoring additional " Michael Roth
2021-02-03  0:38   ` Sean Christopherson [this message]
2021-02-03  8:04     ` Paolo Bonzini
2021-02-02 19:01 ` [PATCH v4 2/3] KVM: SVM: remove uneeded fields from host_save_users_msrs Michael Roth
2021-02-02 19:01 ` [PATCH v4 3/3] KVM: SVM: use .prepare_guest_switch() to handle CPU register save/setup Michael Roth
2021-02-03  8:10 ` [PATCH v4 0/3] KVM: SVM: Refactor vcpu_load/put to use vmload/vmsave for host state Paolo Bonzini

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