From: Sean Christopherson <seanjc@google.com>
To: Binbin Wu <binbin.wu@linux.intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Kiryl Shutsemau <kas@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
kvm@vger.kernel.org, x86@kernel.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org,
Sashiko Bot <sashiko-bot@kernel.org>,
Joerg Roedel <joerg.roedel@amd.com>,
Yan Zhao <yan.y.zhao@intel.com>,
Ackerley Tng <ackerleytng@google.com>
Subject: Re: [PATCH v2 2/2] KVM: TDX: Return EINVAL, not EOPNOTSUPP, for NULL INIT_MEM_REGION source
Date: Wed, 1 Jul 2026 10:12:33 -0700 [thread overview]
Message-ID: <akVKgY6JK9im5aDZ@google.com> (raw)
In-Reply-To: <323a9a1a-6cf9-4a68-b92a-867f497b3d34@linux.intel.com>
On Wed, Jul 01, 2026, Binbin Wu wrote:
> On 7/1/2026 5:37 AM, Sean Christopherson wrote:
> > Return EINVAL instead of EOPNOTSUPP if userspace attempts to pass a NULL
> > pointer for the source page of INIT_MEM_REGION, so that KVM's ABI is
> > consistent between TDX and SNP (for LAUNCH_UPDATE). EOPNOTSUPP was chosen
> > to be a forward-looking error code for when guest_memfd supports in-place
> > conversion, but even when in-place conversion comes along, it's an awkward
> > error code as KVM is deliberately choosing to disallow virtual address '0',
> > which is technically a legal userspace address. I.e. it's not so much a
> > lack of support as it is that KVM reserves address '0' to simplify KVM's
> > internal implementation.
>
> Nit:
> Do you think it's worth calling this out in the documentation?
Yes, though that can be done separate since this series doesn't change ABI.
E.g. we can probably do it opportunistically as part of the in-place conversion
series?
next prev parent reply other threads:[~2026-07-01 17:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-30 21:37 [PATCH v2 0/2] KVM: x86: gmem populate fix and cleanups Sean Christopherson
2026-06-30 21:37 ` [PATCH v2 1/2] KVM: SEV: Explicitly disallow NULL user address for SNP_LAUNCH_UPDATE Sean Christopherson
2026-07-01 21:15 ` Ackerley Tng
2026-07-01 21:22 ` Sean Christopherson
2026-06-30 21:37 ` [PATCH v2 2/2] KVM: TDX: Return EINVAL, not EOPNOTSUPP, for NULL INIT_MEM_REGION source Sean Christopherson
2026-06-30 21:49 ` sashiko-bot
2026-07-01 20:13 ` Ackerley Tng
2026-07-01 20:54 ` Sean Christopherson
2026-07-01 7:27 ` Yan Zhao
2026-07-01 8:02 ` Binbin Wu
2026-07-01 17:12 ` Sean Christopherson [this message]
2026-07-02 1:12 ` Binbin Wu
2026-07-01 9:22 ` Kiryl Shutsemau
2026-07-02 2:32 ` Xiaoyao Li
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