From: Sean Christopherson <seanjc@google.com>
To: Anish Moorthy <amoorthy@google.com>
Cc: pbonzini@redhat.com, maz@kernel.org, oliver.upton@linux.dev,
jthoughton@google.com, bgardon@google.com, dmatlack@google.com,
ricarkol@google.com, axelrasmussen@google.com, peterx@redhat.com,
kvm@vger.kernel.org, kvmarm@lists.linux.dev
Subject: Re: [PATCH v3 04/22] KVM: x86: Set vCPU exit reason to KVM_EXIT_UNKNOWN at the start of KVM_RUN
Date: Tue, 2 May 2023 15:31:22 -0700 [thread overview]
Message-ID: <ZFGPOiip/Sf8V8DU@google.com> (raw)
In-Reply-To: <CAF7b7moeysHUtiS_5DL9c5OPKnCsiO50zBkjp1m4QjVTvXF58A@mail.gmail.com>
On Tue, May 02, 2023, Anish Moorthy wrote:
> On Tue, May 2, 2023 at 1:41 PM Sean Christopherson <seanjc@google.com> wrote:
> >
> > If KVM triggers a WARN_ON_ONCE(), then that's an issue. Though looking at the
> > code, the cui() aspect is a moot point. As I stated in the previous discussion,
> > the WARN_ON_ONCE() in question needs to be off-by-default.
> >
> > : Hmm, one idea would be to have the initial -EFAULT detection fill kvm_run.memory_fault,
> > : but set kvm_run.exit_reason to some magic number, e.g. zero it out. Then KVM could
> > : WARN if something tries to overwrite kvm_run.exit_reason. The WARN would need to
> > : be buried by a Kconfig or something since kvm_run can be modified by userspace,
> > : but other than that I think it would work.
>
> Ah, ok: I thought using WARN_ON_ONCE instead of WARN might have
> obviated the Kconfig. I'll go add one.
Don't put too much effort into anything at this point. I'm not entirely convinced
that it's worth carrying a Kconfig for this one-off case (my "suggestion" was mostly
just me spitballing), and at a quick glance through the rest of the series, I'll
definitely have more comments when I do a full review, i.e. things may change too.
next prev parent reply other threads:[~2023-05-02 22:31 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-12 21:34 [PATCH v3 00/22] Improve scalability of KVM + userfaultfd live migration via annotated memory faults Anish Moorthy
2023-04-12 21:34 ` [PATCH v3 01/22] KVM: selftests: Allow many vCPUs and reader threads per UFFD in demand paging test Anish Moorthy
2023-04-19 13:51 ` Hoo Robert
2023-04-20 17:55 ` Anish Moorthy
2023-04-21 12:15 ` Robert Hoo
2023-04-21 16:21 ` Anish Moorthy
2023-04-12 21:34 ` [PATCH v3 02/22] KVM: selftests: Use EPOLL in userfaultfd_util reader threads and signal errors via TEST_ASSERT Anish Moorthy
2023-04-19 13:36 ` Hoo Robert
2023-04-19 23:26 ` Anish Moorthy
2023-04-12 21:34 ` [PATCH v3 03/22] KVM: Allow hva_pfn_fast() to resolve read-only faults Anish Moorthy
2023-04-12 21:34 ` [PATCH v3 04/22] KVM: x86: Set vCPU exit reason to KVM_EXIT_UNKNOWN at the start of KVM_RUN Anish Moorthy
2023-05-02 17:17 ` Anish Moorthy
2023-05-02 18:51 ` Sean Christopherson
2023-05-02 19:49 ` Anish Moorthy
2023-05-02 20:41 ` Sean Christopherson
2023-05-02 21:46 ` Anish Moorthy
2023-05-02 22:31 ` Sean Christopherson [this message]
2023-04-12 21:34 ` [PATCH v3 05/22] KVM: Add KVM_CAP_MEMORY_FAULT_INFO Anish Moorthy
2023-04-19 13:57 ` Hoo Robert
2023-04-20 18:09 ` Anish Moorthy
2023-04-21 12:28 ` Robert Hoo
2023-06-01 19:52 ` Oliver Upton
2023-06-01 20:30 ` Anish Moorthy
2023-06-01 21:29 ` Oliver Upton
2023-07-04 10:10 ` Kautuk Consul
2023-04-12 21:34 ` [PATCH v3 06/22] KVM: Add docstrings to __kvm_write_guest_page() and __kvm_read_guest_page() Anish Moorthy
2023-04-12 21:34 ` [PATCH v3 07/22] KVM: Annotate -EFAULTs from kvm_vcpu_write_guest_page() Anish Moorthy
2023-04-20 20:52 ` Peter Xu
2023-04-20 23:29 ` Anish Moorthy
2023-04-21 15:00 ` Peter Xu
2023-04-12 21:34 ` [PATCH v3 08/22] KVM: Annotate -EFAULTs from kvm_vcpu_read_guest_page() Anish Moorthy
2023-04-12 21:34 ` [PATCH v3 09/22] KVM: Annotate -EFAULTs from kvm_vcpu_map() Anish Moorthy
2023-04-20 20:53 ` Peter Xu
2023-04-20 23:34 ` Anish Moorthy
2023-04-21 14:58 ` Peter Xu
2023-04-12 21:34 ` [PATCH v3 10/22] KVM: x86: Annotate -EFAULTs from kvm_mmu_page_fault() Anish Moorthy
2023-04-12 21:34 ` [PATCH v3 11/22] KVM: x86: Annotate -EFAULTs from setup_vmgexit_scratch() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 12/22] KVM: x86: Annotate -EFAULTs from kvm_handle_page_fault() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 13/22] KVM: x86: Annotate -EFAULTs from kvm_hv_get_assist_page() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 14/22] KVM: x86: Annotate -EFAULTs from kvm_pv_clock_pairing() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 15/22] KVM: x86: Annotate -EFAULTs from direct_map() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 16/22] KVM: x86: Annotate -EFAULTs from kvm_handle_error_pfn() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 17/22] KVM: Introduce KVM_CAP_ABSENT_MAPPING_FAULT without implementation Anish Moorthy
2023-04-19 14:00 ` Hoo Robert
2023-04-20 18:23 ` Anish Moorthy
2023-04-24 21:02 ` Sean Christopherson
2023-06-01 16:04 ` Oliver Upton
2023-06-01 18:19 ` Oliver Upton
2023-06-01 18:59 ` Sean Christopherson
2023-06-01 19:29 ` Oliver Upton
2023-06-01 19:34 ` Sean Christopherson
2023-04-12 21:35 ` [PATCH v3 18/22] KVM: x86: Implement KVM_CAP_ABSENT_MAPPING_FAULT Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 19/22] KVM: arm64: Annotate (some) -EFAULTs from user_mem_abort() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 20/22] KVM: arm64: Implement KVM_CAP_ABSENT_MAPPING_FAULT Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 21/22] KVM: selftests: Add memslot_flags parameter to memstress_create_vm() Anish Moorthy
2023-04-12 21:35 ` [PATCH v3 22/22] KVM: selftests: Handle memory fault exits in demand_paging_test Anish Moorthy
2023-04-19 14:09 ` Hoo Robert
2023-04-19 16:40 ` Anish Moorthy
2023-04-20 22:47 ` Anish Moorthy
2023-04-27 15:48 ` James Houghton
2023-05-01 18:01 ` Anish Moorthy
2023-04-19 19:55 ` [PATCH v3 00/22] Improve scalability of KVM + userfaultfd live migration via annotated memory faults Peter Xu
2023-04-19 20:15 ` Axel Rasmussen
2023-04-19 21:05 ` Peter Xu
[not found] ` <CAF7b7mo68VLNp=QynfT7QKgdq=d1YYGv1SEVEDxF9UwHzF6YDw@mail.gmail.com>
2023-04-20 21:29 ` Peter Xu
2023-04-21 16:58 ` Anish Moorthy
2023-04-21 17:39 ` Nadav Amit
2023-04-24 17:54 ` Anish Moorthy
2023-04-24 19:44 ` Nadav Amit
2023-04-24 20:35 ` Sean Christopherson
2023-04-24 23:47 ` Nadav Amit
2023-04-25 0:26 ` Sean Christopherson
2023-04-25 0:37 ` Nadav Amit
2023-04-25 0:15 ` Anish Moorthy
2023-04-25 0:54 ` Nadav Amit
2023-04-27 16:38 ` James Houghton
2023-04-27 20:26 ` Peter Xu
2023-05-03 19:45 ` Anish Moorthy
2023-05-03 20:09 ` Sean Christopherson
[not found] ` <ZFLPlRReglM/Vgfu@x1n>
2023-05-03 21:27 ` Peter Xu
2023-05-03 21:42 ` Sean Christopherson
2023-05-03 23:45 ` Peter Xu
2023-05-04 19:09 ` Peter Xu
2023-05-05 18:32 ` Anish Moorthy
2023-05-08 1:23 ` Peter Xu
2023-05-09 20:52 ` Anish Moorthy
2023-05-10 21:50 ` Peter Xu
2023-05-11 17:17 ` David Matlack
2023-05-11 17:33 ` Axel Rasmussen
2023-05-11 19:05 ` David Matlack
2023-05-11 19:45 ` Axel Rasmussen
2023-05-15 15:16 ` Peter Xu
2023-05-15 15:05 ` Peter Xu
2023-05-15 17:16 ` Anish Moorthy
2023-05-05 20:05 ` Nadav Amit
2023-05-08 1:12 ` Peter Xu
2023-04-20 23:42 ` Anish Moorthy
2023-05-09 22:19 ` David Matlack
2023-05-10 16:35 ` Anish Moorthy
2023-05-10 22:35 ` Sean Christopherson
2023-05-10 23:44 ` Anish Moorthy
2023-05-23 17:49 ` Anish Moorthy
2023-06-01 22:43 ` Oliver Upton
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