Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
Message-ID: <8b3b34a6-3aba-8471-453b-f15935edf438@redhat.com>
Date:   Wed, 24 Nov 2021 19:20:09 +0100
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Subject: Re: [PATCH MANUALSEL 5.15 1/8] KVM: X86: Fix tlb flush for tdp in
 kvm_invalidate_pcid()
Content-Language: en-US
To:     Sasha Levin <sashal@kernel.org>, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Cc:     Lai Jiangshan <laijs@linux.alibaba.com>, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        x86@kernel.org, kvm@vger.kernel.org
References: <20211123163630.289306-1-sashal@kernel.org>
From:   Paolo Bonzini <pbonzini@redhat.com>
In-Reply-To: <20211123163630.289306-1-sashal@kernel.org>
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On 11/23/21 17:36, Sasha Levin wrote:
> From: Lai Jiangshan <laijs@linux.alibaba.com>
> 
> [ Upstream commit e45e9e3998f0001079b09555db5bb3b4257f6746 ]
> 
> The KVM doesn't know whether any TLB for a specific pcid is cached in
> the CPU when tdp is enabled.  So it is better to flush all the guest
> TLB when invalidating any single PCID context.
> 
> The case is very rare or even impossible since KVM generally doesn't
> intercept CR3 write or INVPCID instructions when tdp is enabled, so the
> fix is mostly for the sake of overall robustness.
> 
> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
> Message-Id: <20211019110154.4091-2-jiangshanlai@gmail.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

Acked-by: Paolo Bonzini <pbonzini@redhat.com>

for this patch, but not to all the others.

Paolo