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From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
	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>,
	Sean Christopherson <seanjc@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	x86@kernel.org, Xiaoyao Li <xiaoyao.li@intel.com>
Subject: [PATCH 1/2] x86/virt/tdx: Remove __user annotation from kernel pointer
Date: Wed, 29 Oct 2025 12:48:31 -0700	[thread overview]
Message-ID: <20251029194831.6819B2E7@davehans-spike.ostc.intel.com> (raw)
In-Reply-To: <20251029194829.F79F929D@davehans-spike.ostc.intel.com>


From: Dave Hansen <dave.hansen@linux.intel.com>

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'.

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>
Cc: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Kirill A. Shutemov" <kas@kernel.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---

 b/arch/x86/kvm/vmx/tdx.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff -puN arch/x86/kvm/vmx/tdx.c~tdx-sparse-fix-3 arch/x86/kvm/vmx/tdx.c
--- a/arch/x86/kvm/vmx/tdx.c~tdx-sparse-fix-3	2025-10-29 12:10:10.375383704 -0700
+++ b/arch/x86/kvm/vmx/tdx.c	2025-10-29 12:10:10.379384154 -0700
@@ -3054,7 +3054,8 @@ static int tdx_vcpu_get_cpuid_leaf(struc
 
 static int tdx_vcpu_get_cpuid(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *cmd)
 {
-	struct kvm_cpuid2 __user *output, *td_cpuid;
+	struct kvm_cpuid2 __user *output;
+	struct kvm_cpuid2 *td_cpuid;
 	int r = 0, i = 0, leaf;
 	u32 level;
 
_

  reply	other threads:[~2025-10-29 19:48 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-29 19:48 [PATCH 0/2] x86/virt/tdx: Minor sparse fixups Dave Hansen
2025-10-29 19:48 ` Dave Hansen [this message]
2025-10-29 21:06   ` [PATCH 1/2] x86/virt/tdx: Remove __user annotation from kernel pointer Edgecombe, Rick P
2025-10-29 21:13     ` Dave Hansen
2025-10-29 23:00       ` Sean Christopherson
2025-10-29 23:34         ` Dave Hansen
2025-10-30  0:04           ` Sean Christopherson
2025-10-29 19:48 ` [PATCH 2/2] x86/virt/tdx: Fix sparse warnings from using 0 for NULL Dave Hansen
2025-10-29 21:09   ` Edgecombe, Rick P
2025-10-29 20:53 ` [PATCH 0/2] x86/virt/tdx: Minor sparse fixups Edgecombe, Rick P
2025-10-29 21:10   ` Edgecombe, Rick P

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