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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 09/10] KVM: VMX: Skip additional Hyper-V TLB EPTP flushes if one fails
Date: Wed, 21 Oct 2020 16:22:47 +0200	[thread overview]
Message-ID: <87lffz4q14.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20201020215613.8972-10-sean.j.christopherson@intel.com>

Sean Christopherson <sean.j.christopherson@intel.com> writes:

> Skip additional EPTP flushes if one fails when processing EPTPs for
> Hyper-V's paravirt TLB flushing.  If _any_ flush fails, KVM falls back
> to a full global flush, i.e. additional flushes are unnecessary (and
> will likely fail anyways).
>
> Continue processing the loop unless a mismatch was already detected,
> e.g. to handle the case where the first flush fails and there is a
> yet-to-be-detected mismatch.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/x86/kvm/vmx/vmx.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index a45a90d44d24..e0fea09a6e42 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -517,7 +517,11 @@ static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
>  			else
>  				mismatch = true;
>  
> -			ret |= hv_remote_flush_eptp(tmp_eptp, range);
> +			if (!ret)
> +				ret = hv_remote_flush_eptp(tmp_eptp, range);
> +
> +			if (ret && mismatch)
> +				break;
>  		}
>  		if (mismatch)
>  			kvm_vmx->hv_tlb_eptp = INVALID_PAGE;

In case my suggestion on PATCH5 gets dismissed,

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

-- 
Vitaly


  reply	other threads:[~2020-10-21 14:22 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20 21:56 [PATCH v2 00/10] KVM: VMX: Clean up Hyper-V PV TLB flush Sean Christopherson
2020-10-20 21:56 ` [PATCH v2 01/10] KVM: VMX: Track common EPTP for Hyper-V's paravirt " Sean Christopherson
2020-10-21 11:57   ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 02/10] KVM: VMX: Stash kvm_vmx in a local variable for Hyper-V " Sean Christopherson
2020-10-21 12:00   ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 03/10] KVM: VMX: Fold Hyper-V EPTP checking into it's only caller Sean Christopherson
2020-10-21 12:08   ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 04/10] KVM: VMX: Do Hyper-V TLB flush iff vCPU's EPTP hasn't been flushed Sean Christopherson
2020-10-21 12:23   ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 05/10] KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatch Sean Christopherson
2020-10-21 12:39   ` Vitaly Kuznetsov
2020-10-21 16:38     ` Sean Christopherson
2020-10-22  9:03       ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 06/10] KVM: VMX: Don't invalidate hv_tlb_eptp if the new EPTP matches Sean Christopherson
2020-10-21 13:47   ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 07/10] KVM: VMX: Explicitly check for hv_remote_flush_tlb when loading pgd Sean Christopherson
     [not found]   ` <87r1pr4q8z.fsf@vitty.brq.redhat.com>
2020-10-21 17:30     ` Sean Christopherson
2020-10-20 21:56 ` [PATCH v2 08/10] KVM: VMX: Define Hyper-V paravirt TLB flush fields iff Hyper-V is enabled Sean Christopherson
2020-10-21 14:20   ` Vitaly Kuznetsov
2020-10-20 21:56 ` [PATCH v2 09/10] KVM: VMX: Skip additional Hyper-V TLB EPTP flushes if one fails Sean Christopherson
2020-10-21 14:22   ` Vitaly Kuznetsov [this message]
2020-10-20 21:56 ` [PATCH v2 10/10] KVM: VMX: Track PGD instead of EPTP for paravirt Hyper-V TLB flush Sean Christopherson
     [not found]   ` <87imb34p9b.fsf@vitty.brq.redhat.com>
2020-10-21 17:59     ` Sean Christopherson
2020-10-21  9:18 ` [PATCH v2 00/10] KVM: VMX: Clean up Hyper-V PV " Vitaly Kuznetsov

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