From: Sean Christopherson <seanjc@google.com>
To: Yan Zhao <yan.y.zhao@intel.com>
Cc: pbonzini@redhat.com, rick.p.edgecombe@intel.com,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH 3/4] KVM: x86/mmu: Make sure pfn is not changed for spurious fault
Date: Fri, 7 Feb 2025 07:07:06 -0800 [thread overview]
Message-ID: <Z6Yhmg2nmUAtp4yn@google.com> (raw)
In-Reply-To: <20250207030900.1808-1-yan.y.zhao@intel.com>
On Fri, Feb 07, 2025, Yan Zhao wrote:
> Make sure pfn is not changed for a spurious fault by warning in the TDP
> MMU. For shadow path, only treat a prefetch fault as spurious when pfn is
> not changed, since the rmap removal and add are required when pfn is
> changed.
I like sanity checks, but I don't like special casing "prefetch" faults like this.
KVM should _never_ change the PFN of a shadow-present SPTE. The TDP MMU already
BUG()s on this, and mmu_spte_update() WARNs on the transition.
next prev parent reply other threads:[~2025-02-07 15:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-07 3:06 [PATCH 0/4] Small changes related to prefetch and spurious faults Yan Zhao
2025-02-07 3:07 ` [PATCH 1/4] KVM: x86/mmu: Further check old SPTE is leaf for spurious prefetch fault Yan Zhao
2025-02-07 3:08 ` [PATCH 2/4] KVM: x86/tdp_mmu: Merge the prefetch into the is_access_allowed() check Yan Zhao
2025-02-07 15:03 ` Sean Christopherson
2025-02-08 2:29 ` Yan Zhao
2025-02-10 22:17 ` Sean Christopherson
2025-02-07 3:09 ` [PATCH 3/4] KVM: x86/mmu: Make sure pfn is not changed for spurious fault Yan Zhao
2025-02-07 15:07 ` Sean Christopherson [this message]
2025-02-08 2:37 ` Yan Zhao
2025-02-10 22:23 ` Sean Christopherson
2025-02-11 6:48 ` Yan Zhao
2025-02-07 3:09 ` [PATCH 4/4] KVM: x86/mmu: Free obsolete roots when pre-faulting SPTEs Yan Zhao
2025-02-07 15:12 ` Sean Christopherson
2025-02-08 3:01 ` Yan Zhao
2025-02-10 22:41 ` Sean Christopherson
2025-02-11 5:38 ` Yan Zhao
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