From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Ackerley Tng <ackerleytng@google.com>,
Fuad Tabba <tabba@google.com>, Xiaoyao Li <xiaoyao.li@intel.com>,
Binbin Wu <binbin.wu@linux.intel.com>,
Shivank Garg <shivankg@amd.com>, Yan Zhao <yan.y.zhao@intel.com>
Subject: Re: [PATCH 0/3] KVM: Kconfig fixes for the VM-wide private memory attribute
Date: Tue, 20 Oct 2026 21:57:53 -0700 [thread overview]
Message-ID: <athGUdkDw6rSatUW@google.com> (raw)
In-Reply-To: <20261020131447.122096-1-pbonzini@redhat.com>
On Tue, Oct 20, 2026, Paolo Bonzini wrote:
> A late review of the guest_memfd attributes changes...
>
> With Linux 7.4 the "private" memory attribute was moved from the VM
> to the individual guest_memfd file descriptor. The old semantics are
> available for backwards compatibility via CONFIG_KVM_VM_MEMORY_ATTRIBUTES,
> and disabled by default.
>
> This change has two problems: first, it ties support for VM memory
> attributes entirely to a backwards compatibility symbol for distros.
> Second, it is incompatible with all released versions of QEMU (and
> perhaps most other VMMs?), thus the default is arguably not the
> right one.
I was hoping we could go with a stick approach, but given how painful double-allocating
is, hopefully a carrot will work too. :-)
prev parent reply other threads:[~2026-10-21 4:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-20 13:14 Paolo Bonzini
2026-10-20 13:14 ` [PATCH 1/3] KVM: split CONFIG_KVM_PRIVATE_MEMATTR_VM out of KVM_VM_MEMORY_ATTRIBUTES Paolo Bonzini
2026-10-21 7:01 ` Xiaoyao Li
2026-10-20 13:14 ` [PATCH 2/3] KVM: x86: leave the legacy private attribute in for TDX and SEV Paolo Bonzini
2026-10-21 7:05 ` Xiaoyao Li
2026-10-20 13:14 ` [PATCH 3/3] KVM: always make in-place conversion a compile-time constant when possible Paolo Bonzini
2026-10-21 7:07 ` Xiaoyao Li
2026-10-21 7:12 ` Paolo Bonzini
2026-10-21 4:57 ` Sean Christopherson [this message]
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