From: Sean Christopherson <seanjc@google.com>
To: Anish Moorthy <amoorthy@google.com>
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH 6/8] kvm/x86: Add mem fault exit on EPT violations
Date: Thu, 23 Feb 2023 12:11:02 -0800 [thread overview]
Message-ID: <Y/fIVp5GUS35vCH1@google.com> (raw)
In-Reply-To: <CAF7b7mor-QHwLCLQ_sp4sOJTztRGVOzpBupeuiCicA3YG=-TTQ@mail.gmail.com>
On Wed, Feb 22, 2023, Anish Moorthy wrote:
> On Wed, Feb 15, 2023 at 9:24 AM Sean Christopherson <seanjc@google.com> wrote:
> >
> > On Wed, Feb 15, 2023, Anish Moorthy wrote:
> > > + if (mem_fault_nowait) {
> > > + if (fault->pfn == KVM_PFN_ERR_FAULT) {
> > > + vcpu->run->exit_reason = KVM_EXIT_MEMORY_FAULT;
> > > + vcpu->run->memory_fault.gpa = fault->gfn << PAGE_SHIFT;
> > > + vcpu->run->memory_fault.size = PAGE_SIZE;
> >
> > This belongs in a separate patch, and the exit stuff should be filled in by
> > kvm_handle_error_pfn(). Then this if-statement goes away entirely because the
> > "if (!async)" will always evaluate true in the nowait case.
>
> Hi Sean, what exactly did you want "in a separate patch"?
Separate "exit if fast gup() fails", a.k.a. nowait, from "exit with KVM_EXIT_MEMORY_FAULT
instead of -EFAULT on errors". I.e. don't tie KVM_EXIT_MEMORY_FAULT to the fast
gup() capability (or memslot flag?). That way filing vcpu->run->memory_fault
lands in a separate, largely generic patch, and this patch only introduces the
fast gup() logic.
That probably means adding yet another capability, but capabilities are cheap.
next prev parent reply other threads:[~2023-02-23 20:11 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-15 1:16 [PATCH 0/8] Add memory fault exits to avoid slow GUP Anish Moorthy
2023-02-15 1:16 ` [PATCH 1/8] selftests/kvm: Fix bug in how demand_paging_test calculates paging rate Anish Moorthy
2023-02-15 7:27 ` Oliver Upton
2023-02-15 16:44 ` Sean Christopherson
2023-02-15 18:05 ` Anish Moorthy
2023-02-15 1:16 ` [PATCH 2/8] selftests/kvm: Allow many vcpus per UFFD in demand paging test Anish Moorthy
2023-02-15 1:16 ` [PATCH 3/8] selftests/kvm: Switch demand paging uffd readers to epoll Anish Moorthy
2023-02-15 1:16 ` [PATCH 4/8] kvm: Allow hva_pfn_fast to resolve read-only faults Anish Moorthy
2023-02-15 9:01 ` Oliver Upton
2023-02-15 17:03 ` Sean Christopherson
2023-02-15 18:19 ` Anish Moorthy
2023-02-15 1:16 ` [PATCH 5/8] kvm: Add cap/kvm_run field for memory fault exits Anish Moorthy
2023-02-15 8:41 ` Marc Zyngier
2023-02-15 17:07 ` Sean Christopherson
2023-02-16 18:53 ` Anish Moorthy
2023-02-16 21:38 ` Sean Christopherson
2023-02-17 19:14 ` Anish Moorthy
2023-02-17 20:33 ` Sean Christopherson
2023-02-23 1:16 ` Anish Moorthy
2023-02-23 20:55 ` Sean Christopherson
2023-02-23 23:03 ` Anish Moorthy
2023-02-24 0:01 ` Sean Christopherson
2023-02-17 20:47 ` Sean Christopherson
2023-02-15 8:59 ` Oliver Upton
2023-02-15 1:16 ` [PATCH 6/8] kvm/x86: Add mem fault exit on EPT violations Anish Moorthy
2023-02-15 17:23 ` Sean Christopherson
2023-02-16 22:55 ` Peter Xu
2023-02-23 0:35 ` Anish Moorthy
2023-02-23 20:11 ` Sean Christopherson [this message]
2023-02-15 1:16 ` [PATCH 7/8] kvm/arm64: Implement KVM_CAP_MEM_FAULT_NOWAIT for arm64 Anish Moorthy
2023-02-15 18:24 ` Oliver Upton
2023-02-15 23:28 ` Anish Moorthy
2023-02-15 23:37 ` Oliver Upton
2023-02-15 1:16 ` [PATCH 8/8] selftests/kvm: Handle mem fault exits in demand paging test Anish Moorthy
2023-02-15 1:46 ` [PATCH 0/8] Add memory fault exits to avoid slow GUP James Houghton
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