From: Sean Christopherson <seanjc@google.com>
To: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
"Kirill A. Shutemov" <kas@kernel.org>,
kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org
Subject: Re: [v2][PATCH 1/2] x86/virt/tdx: Remove __user annotation from kernel pointer
Date: Tue, 4 Nov 2025 08:31:02 -0800 [thread overview]
Message-ID: <aQoqRqb-vN5GxT-x@google.com> (raw)
In-Reply-To: <72503421-803c-4fa8-8e28-b0c793798c7c@intel.com>
On Tue, Nov 04, 2025, Xiaoyao Li wrote:
> On 11/4/2025 7:44 AM, Dave Hansen wrote:
> >
> > From: Dave Hansen <dave.hansen@linux.intel.com>
> >
> > Separate __user pointer variable declaration from kernel one.
> >
> > There are two 'kvm_cpuid2' pointers involved here. There's an "input"
> > side: 'td_cpuid' which is a normal kernel pointer and an 'output'
> > side. The output here is userspace and there is an attempt at properly
> > annotating the variable with __user:
> >
> > struct kvm_cpuid2 __user *output, *td_cpuid;
> >
> > But, alas, this is wrong. The __user in the definition applies to both
> > 'output' and 'td_cpuid'. Sparse notices the address space mismatch and
> > will complain about it.
> >
> > Fix it up by completely separating the two definitions so that it is
> > obviously correct without even having to know what the C syntax rules
> > even are.
> >
> > Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> > Fixes: 488808e682e7 ("KVM: x86: Introduce KVM_TDX_GET_CPUID")
> > Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
>
> the prefix of the shortlog is still "x86/virt/tdx". I think Sean will change
> it to "KVM: TDX:", if it gets routed through KVM tree.
Ya, I'll fixup when applying.
next prev parent reply other threads:[~2025-11-04 16:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-03 23:44 [v2][PATCH 0/2] x86/virt/tdx: Minor sparse fixups Dave Hansen
2025-11-03 23:44 ` [v2][PATCH 1/2] x86/virt/tdx: Remove __user annotation from kernel pointer Dave Hansen
2025-11-04 9:23 ` Kiryl Shutsemau
2025-11-04 9:55 ` Xiaoyao Li
2025-11-04 16:31 ` Sean Christopherson [this message]
2025-11-03 23:44 ` [v2][PATCH 2/2] x86/virt/tdx: Fix sparse warnings from using 0 for NULL Dave Hansen
2025-11-04 9:24 ` Kiryl Shutsemau
2025-11-04 9:56 ` Xiaoyao Li
2025-11-18 23:27 ` [v2][PATCH 0/2] x86/virt/tdx: Minor sparse fixups Sean Christopherson
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