From: Oliver Upton <oliver.upton@linux.dev>
To: Anish Moorthy <amoorthy@google.com>
Cc: Sean Christopherson <seanjc@google.com>,
David Matlack <dmatlack@google.com>,
maz@kernel.org, kvm@vger.kernel.org, kvmarm@lists.linux.dev,
robert.hoo.linux@gmail.com, jthoughton@google.com,
axelrasmussen@google.com, peterx@redhat.com,
nadav.amit@gmail.com, isaku.yamahata@gmail.com,
kconsul@linux.vnet.ibm.com
Subject: Re: [PATCH v7 06/14] KVM: Add memslot flag to let userspace force an exit on missing hva mappings
Date: Mon, 11 Mar 2024 21:21:28 +0000 [thread overview]
Message-ID: <Ze912ONhTo99RRpR@linux.dev> (raw)
In-Reply-To: <CAF7b7mpgeLJudcT9YhjQOqsXxz07Y9PY1a-F0ts6oVsVJwrnpA@mail.gmail.com>
On Mon, Mar 11, 2024 at 10:08:56AM -0700, Anish Moorthy wrote:
> I think patches 10/11/12 are useful changes to the selftest that make
> sense to merge even with KVM_MEM_EXIT_ON_MISSING being mothballed-
> they should rebase without any issues. And the annotations on the
> stage-2 fault handlers seem like they should still be added, but I
> suppose David can do that with his series.
Yeah, let's fold the vCPU exit portions of the UAPI into the overall KVM
userfault series. In that case there is sufficient context at the time
of the "memory fault" to generate a 'precise' fault context (this GFN
failed since it isn't marked as present).
Compare that to the current implementation, which actually annotates
_any_ __gfn_to_pfn_memslot() failures on the way out to userspace. I
haven't seen anyone saying their userspace wants to use this, and I'd
rather not take a new feature without a user, even if it is comparably
trivial.
--
Thanks,
Oliver
next prev parent reply other threads:[~2024-03-11 21:21 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 23:53 [PATCH v7 00/14] Improve KVM + userfaultfd performance via KVM_EXIT_MEMORY_FAULTs on stage-2 faults Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 01/14] KVM: Clarify meaning of hva_to_pfn()'s 'atomic' parameter Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 02/14] KVM: Add function comments for __kvm_read/write_guest_page() Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 03/14] KVM: Documentation: Make note of the KVM_MEM_GUEST_MEMFD memslot flag Anish Moorthy
2024-04-09 22:47 ` Sean Christopherson
2024-02-15 23:53 ` [PATCH v7 04/14] KVM: Simplify error handling in __gfn_to_pfn_memslot() Anish Moorthy
2024-04-09 22:44 ` Sean Christopherson
2024-02-15 23:53 ` [PATCH v7 05/14] KVM: Define and communicate KVM_EXIT_MEMORY_FAULT RWX flags to userspace Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 06/14] KVM: Add memslot flag to let userspace force an exit on missing hva mappings Anish Moorthy
2024-03-08 22:07 ` Sean Christopherson
2024-03-09 0:46 ` David Matlack
2024-03-11 4:45 ` Oliver Upton
2024-03-11 16:20 ` David Matlack
2024-07-03 17:34 ` Nikita Kalyazin
2024-07-03 20:11 ` David Matlack
2024-07-04 10:10 ` Nikita Kalyazin
2024-03-11 16:36 ` Sean Christopherson
2024-03-11 17:08 ` Anish Moorthy
2024-03-11 21:21 ` Oliver Upton [this message]
2024-02-15 23:53 ` [PATCH v7 07/14] KVM: x86: Enable KVM_CAP_EXIT_ON_MISSING and annotate EFAULTs from stage-2 fault handler Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 08/14] KVM: arm64: Enable KVM_CAP_MEMORY_FAULT_INFO and annotate fault in the " Anish Moorthy
2024-03-04 20:00 ` Oliver Upton
2024-03-04 20:10 ` Oliver Upton
2024-03-04 20:32 ` Sean Christopherson
2024-03-04 21:03 ` Oliver Upton
2024-03-04 22:49 ` Sean Christopherson
2024-03-05 1:01 ` Oliver Upton
2024-03-05 15:39 ` Sean Christopherson
2024-02-15 23:54 ` [PATCH v7 09/14] KVM: arm64: Implement and advertise KVM_CAP_EXIT_ON_MISSING Anish Moorthy
2024-02-15 23:54 ` [PATCH v7 10/14] KVM: selftests: Report per-vcpu demand paging rate from demand paging test Anish Moorthy
2024-04-09 22:49 ` Sean Christopherson
2024-02-15 23:54 ` [PATCH v7 11/14] KVM: selftests: Allow many vCPUs and reader threads per UFFD in " Anish Moorthy
2024-04-09 22:58 ` Sean Christopherson
2024-02-15 23:54 ` [PATCH v7 12/14] KVM: selftests: Use EPOLL in userfaultfd_util reader threads and signal errors via TEST_ASSERT Anish Moorthy
2024-02-15 23:54 ` [PATCH v7 13/14] KVM: selftests: Add memslot_flags parameter to memstress_create_vm() Anish Moorthy
2024-02-15 23:54 ` [PATCH v7 14/14] KVM: selftests: Handle memory fault exits in demand_paging_test Anish Moorthy
2024-02-16 7:36 ` [PATCH v7 00/14] Improve KVM + userfaultfd performance via KVM_EXIT_MEMORY_FAULTs on stage-2 faults Gupta, Pankaj
2024-02-16 20:00 ` Anish Moorthy
2024-02-16 23:40 ` Axel Rasmussen
2024-02-21 7:35 ` Gupta, Pankaj
2024-04-10 0:19 ` Sean Christopherson
2024-05-07 17:38 ` Anish Moorthy
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