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From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH] kvm: nVMX: Update MSR load counts on a VMCS switch
Date: Fri, 7 Oct 2016 14:15:30 +0200	[thread overview]
Message-ID: <20161007121525.GA12834@potion> (raw)
In-Reply-To: <1475603318-559-1-git-send-email-jmattson@google.com>

2016-10-04 10:48-0700, Jim Mattson:
> When L0 establishes (or removes) an MSR entry in the VM-entry or VM-exit
> MSR load lists, the change should affect the dormant VMCS as well as the
> current VMCS. Moreover, the vmcs02 MSR-load addresses should be
> initialized.
> 
> Signed-off-by: Jim Mattson <jmattson@google.com>
> ---

The fixes seem correct and nested performance is already sad, so
continually overwriting few constants won't hurt ...

Applied to kvm/queue, thanks.

> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> @@ -9928,6 +9928,15 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
>  	vmx_set_constant_host_state(vmx);
>  
>  	/*
> +	 * Set the MSR load/store lists to match L0's settings.
> +	 */
> +	vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0);
> +	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
> +	vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host));
> +	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
> +	vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest));
> +	/*
>  	 * HOST_RSP is normally set correctly in vmx_vcpu_run() just before
>  	 * entry, but only if the current (host) sp changed from the value
>  	 * we wrote last (vmx->host_rsp). This cache is no longer relevant
> @@ -10754,6 +10763,8 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
>  	load_vmcs12_host_state(vcpu, vmcs12);
>  
>  	/* Update any VMCS fields that might have changed while L2 ran */
> +	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
> +	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
>  	vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_tsc_offset);
>  	if (vmx->hv_deadline_tsc == -1)
>  		vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL,
> -- 
> 2.8.0.rc3.226.g39d4020
> 
> --
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      reply	other threads:[~2016-10-07 12:16 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-04 17:48 [PATCH] kvm: nVMX: Update MSR load counts on a VMCS switch Jim Mattson
2016-10-07 12:15 ` Radim Krčmář [this message]

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