From: Yu Zhang <yu.c.zhang@linux.intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Jason Gunthorpe <jgg@nvidia.com>,
Alistair Popple <apopple@nvidia.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 1/3] KVM: VMX: Retry APIC-access page reload if invalidation is in-progress
Date: Sat, 17 Jun 2023 11:45:00 +0800 [thread overview]
Message-ID: <20230617034500.djk5nhmpxony3ngp@linux.intel.com> (raw)
In-Reply-To: <ZIi+jWxYg/UhKpr1@google.com>
>
> > and the backing page is being reclaimed in L0? I saw
> > nested_get_vmcs12_pages() will check vmcs12 and set the APIC access address
> > in VMCS02, but not sure if this routine will be triggered by the mmu
> > notifier...
>
> Pages from vmcs12 that are referenced by physical address in the VMCS are pinned
> (where "pinned" means KVM holds a reference to the page) by kvm_vcpu_map(). I.e.
> the page will not be migrated, and if userspace unmaps the page, userspace might
> break its VM, but that's true for any guest memory that userspace unexpectedly
> unmaps, and there won't be any no use-after-free issues.
>
Thanks, Sean.
About the kvm_vcpu_map(), is it necessary for APIC access address? L0 only
needs to get its pfn, and does not care about the hva or struct page. Could
we just use gfn_to_pfn() to retrieve the pfn, and kvm_release_pfn_clean() to
unpin it later?
B.R.
Yu
next prev parent reply other threads:[~2023-06-17 3:55 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 1:15 [PATCH 0/3] KVM: x86: Use "standard" mmu_notifier hook for APIC page Sean Christopherson
2023-06-02 1:15 ` [PATCH 1/3] KVM: VMX: Retry APIC-access page reload if invalidation is in-progress Sean Christopherson
2023-06-06 2:11 ` Alistair Popple
2023-06-06 17:22 ` Sean Christopherson
2023-06-06 17:39 ` Jason Gunthorpe
2023-06-07 7:40 ` yu.c.zhang
2023-06-07 14:30 ` Sean Christopherson
2023-06-07 17:23 ` Yu Zhang
2023-06-07 17:53 ` Sean Christopherson
2023-06-08 7:00 ` Yu Zhang
2023-06-13 19:07 ` Sean Christopherson
2023-06-17 3:45 ` Yu Zhang [this message]
2023-06-22 23:02 ` Sean Christopherson
2023-06-02 1:15 ` [PATCH 2/3] KVM: x86: Use standard mmu_notifier invalidate hooks for APIC access page Sean Christopherson
2023-06-06 2:20 ` Alistair Popple
2023-06-02 1:15 ` [PATCH 3/3] KVM: x86/mmu: Trigger APIC-access page reload iff vendor code cares Sean Christopherson
2023-06-05 10:15 ` [PATCH 0/3] KVM: x86: Use "standard" mmu_notifier hook for APIC page Paolo Bonzini
2023-06-06 16:43 ` Jason Gunthorpe
2023-06-07 0:55 ` Sean Christopherson
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