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From: Arnd Bergmann <arnd@kernel.org>
To: David Woodhouse <dwmw2@infradead.org>,
	Paul Durrant <paul@xen.org>,
	Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	Jens Axboe <axboe@kernel.dk>,
	Jan Kara <jack@suse.cz>,
	Christian Brauner <brauner@kernel.org>,
	kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] KVM: x86/xen: fix 32-bit pointer cast
Date: Thu, 22 Feb 2024 11:03:58 +0100
Message-Id: <20240222100412.560961-1-arnd@kernel.org>
Precedence: bulk
MIME-Version: 1.0
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From: Arnd Bergmann <arnd@arndb.de>

shared_info.hva is a 64-bit variable, so casting to a pointer causes
a warning in 32-bit builds:

arch/x86/kvm/xen.c: In function 'kvm_xen_hvm_set_attr':
arch/x86/kvm/xen.c:660:45: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
  660 |                         void __user * hva = (void *)data->u.shared_info.hva;

Replace the cast with a u64_to_user_ptr() call that does the right thing.

Fixes: 01a871852b11 ("KVM: x86/xen: allow shared_info to be mapped by fixed HVA")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/x86/kvm/xen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 01c0fd138d2f..8a04e0ae9245 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -657,7 +657,7 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 						     gfn_to_gpa(gfn), PAGE_SIZE);
 			}
 		} else {
-			void __user * hva = (void *)data->u.shared_info.hva;
+			void __user * hva = u64_to_user_ptr(data->u.shared_info.hva);
 
 			if (!PAGE_ALIGNED(hva) || !access_ok(hva, PAGE_SIZE)) {
 				r = -EINVAL;
-- 
2.39.2