From: Sean Christopherson <seanjc@google.com>
To: David Hildenbrand <david@redhat.com>
Cc: Fuad Tabba <tabba@google.com>, Ira Weiny <ira.weiny@intel.com>,
kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-mm@kvack.org, kvmarm@lists.linux.dev, pbonzini@redhat.com,
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hughd@google.com, jthoughton@google.com, peterx@redhat.com,
pankaj.gupta@amd.com
Subject: Re: [PATCH v12 08/18] KVM: guest_memfd: Allow host to map guest_memfd pages
Date: Wed, 18 Jun 2025 18:50:37 -0700 [thread overview]
Message-ID: <aFNs7fyWn8xWnTDO@google.com> (raw)
In-Reply-To: <aFNsVreb41robgbv@google.com>
On Wed, Jun 18, 2025, Sean Christopherson wrote:
> On Wed, Jun 18, 2025, David Hildenbrand wrote:
> > > Ya, but that's more because guest_memfd only supports MAP_SHARED, versus KVM
> > > really wanting to truly share the memory with the entire system.
> > > Of course, that's also an argument to some extent against USER_MAPPABLE, because
> > > that name assumes we'll never want to support MAP_PRIVATE. But letting userspace
> > > MAP_PRIVATE guest_memfd would completely defeat the purpose of guest_memfd, so
> > > unless I'm forgetting a wrinkle with MAP_PRIVATE vs. MAP_SHARED, that's an
> > > assumption I'm a-ok making.
> >
> > So, first important question, are we okay with adding:
> >
> > "GUEST_MEMFD_FLAG_MMAP": we support the mmap() operation
>
> Probably stating the obvious, but yes, I am.
Heh, my brain is a bit fried. I didn't realize you were asking about
doing s/GUEST_MEMFD_FLAG_MMAPPABLE/GUEST_MEMFD_FLAG_MMAP until I read your other
mail.
Luckily, I 100% agree that GUEST_MEMFD_FLAG_MMAP is way better.
next prev parent reply other threads:[~2025-06-19 1:50 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-11 13:33 [PATCH v12 00/18] KVM: Mapping guest_memfd backed memory at the host for software protected VMs Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 01/18] KVM: Rename CONFIG_KVM_PRIVATE_MEM to CONFIG_KVM_GMEM Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 02/18] KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_KVM_GENERIC_GMEM_POPULATE Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 03/18] KVM: Rename kvm_arch_has_private_mem() to kvm_arch_supports_gmem() Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 04/18] KVM: x86: Rename kvm->arch.has_private_mem to kvm->arch.supports_gmem Fuad Tabba
2025-06-13 13:57 ` Ackerley Tng
2025-06-13 20:35 ` Sean Christopherson
2025-06-16 7:13 ` Fuad Tabba
2025-06-16 14:20 ` David Hildenbrand
2025-06-24 20:51 ` Ackerley Tng
2025-06-25 6:33 ` Roy, Patrick
2025-06-11 13:33 ` [PATCH v12 05/18] KVM: Rename kvm_slot_can_be_private() to kvm_slot_has_gmem() Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 06/18] KVM: Fix comments that refer to slots_lock Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 07/18] KVM: Fix comment that refers to kvm uapi header path Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 08/18] KVM: guest_memfd: Allow host to map guest_memfd pages Fuad Tabba
2025-06-12 16:16 ` Shivank Garg
2025-06-13 21:03 ` Sean Christopherson
2025-06-13 21:18 ` David Hildenbrand
2025-06-13 22:48 ` Sean Christopherson
2025-06-16 6:52 ` Fuad Tabba
2025-06-16 14:16 ` David Hildenbrand
2025-06-17 23:04 ` Sean Christopherson
2025-06-18 11:18 ` Fuad Tabba
2025-06-16 13:44 ` Ira Weiny
2025-06-16 14:03 ` David Hildenbrand
2025-06-16 14:16 ` Fuad Tabba
2025-06-16 14:25 ` David Hildenbrand
2025-06-18 0:40 ` Sean Christopherson
2025-06-18 8:15 ` David Hildenbrand
2025-06-18 9:20 ` Xiaoyao Li
2025-06-18 9:27 ` David Hildenbrand
2025-06-18 9:44 ` Xiaoyao Li
2025-06-18 9:59 ` David Hildenbrand
2025-06-18 10:42 ` Xiaoyao Li
2025-06-18 11:14 ` David Hildenbrand
2025-06-18 12:17 ` Xiaoyao Li
2025-06-18 13:16 ` David Hildenbrand
2025-06-19 1:48 ` Sean Christopherson
2025-06-19 1:50 ` Sean Christopherson [this message]
2025-06-18 9:25 ` David Hildenbrand
2025-06-25 21:47 ` Ackerley Tng
2025-06-11 13:33 ` [PATCH v12 09/18] KVM: guest_memfd: Track shared memory support in memslot Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 10/18] KVM: x86/mmu: Handle guest page faults for guest_memfd with shared memory Fuad Tabba
2025-06-13 22:08 ` Sean Christopherson
2025-06-24 23:40 ` Ackerley Tng
2025-06-27 15:01 ` Ackerley Tng
2025-06-30 8:07 ` Fuad Tabba
2025-06-30 14:44 ` Ackerley Tng
2025-06-30 15:08 ` Fuad Tabba
2025-06-30 19:26 ` Shivank Garg
2025-06-30 20:03 ` David Hildenbrand
2025-07-01 14:15 ` Ackerley Tng
2025-07-01 14:44 ` David Hildenbrand
2025-07-08 0:05 ` Sean Christopherson
2025-07-08 13:44 ` Ackerley Tng
2025-06-11 13:33 ` [PATCH v12 11/18] KVM: x86: Consult guest_memfd when computing max_mapping_level Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 12/18] KVM: x86: Enable guest_memfd shared memory for non-CoCo VMs Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 13/18] KVM: arm64: Refactor user_mem_abort() Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 14/18] KVM: arm64: Handle guest_memfd-backed guest page faults Fuad Tabba
2025-06-12 17:33 ` James Houghton
2025-06-11 13:33 ` [PATCH v12 15/18] KVM: arm64: Enable host mapping of shared guest_memfd memory Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 16/18] KVM: Introduce the KVM capability KVM_CAP_GMEM_SHARED_MEM Fuad Tabba
2025-06-11 13:33 ` [PATCH v12 17/18] KVM: selftests: Don't use hardcoded page sizes in guest_memfd test Fuad Tabba
2025-06-12 16:24 ` Shivank Garg
2025-06-11 13:33 ` [PATCH v12 18/18] KVM: selftests: guest_memfd mmap() test when mapping is allowed Fuad Tabba
2025-06-12 16:23 ` Shivank Garg
2025-06-12 17:38 ` [PATCH v12 00/18] KVM: Mapping guest_memfd backed memory at the host for software protected VMs David Hildenbrand
2025-06-24 10:02 ` Fuad Tabba
2025-06-24 10:16 ` David Hildenbrand
2025-06-24 10:25 ` Fuad Tabba
2025-06-24 11:44 ` David Hildenbrand
2025-06-24 11:58 ` Fuad Tabba
2025-06-24 17:50 ` Sean Christopherson
2025-06-25 8:00 ` Fuad Tabba
2025-06-25 14:07 ` Sean Christopherson
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