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authorSean Christopherson <sean.j.christopherson@intel.com>2020-01-24 15:07:22 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2020-02-05 15:17:45 +0100
commit9b5e85320fcc3af20ce0397b2c6363b6ee5815b6 (patch)
tree3fe4822037bf20c2c43dbdd3f5713622e73a2756 /arch
parent8171cd68806bd2fc28ef688e32fb2a3b3deb04e5 (diff)
KVM: x86: Take a u64 when checking for a valid dr7 value
Take a u64 instead of an unsigned long in kvm_dr7_valid() to fix a build warning on i386 due to right-shifting a 32-bit value by 32 when checking for bits being set in dr7[63:32]. Alternatively, the warning could be resolved by rewriting the check to use an i386-friendly method, but taking a u64 fixes another oddity on 32-bit KVM. Beause KVM implements natural width VMCS fields as u64s to avoid layout issues between 32-bit and 64-bit, a devious guest can stuff vmcs12->guest_dr7 with a 64-bit value even when both the guest and host are 32-bit kernels. KVM eventually drops vmcs12->guest_dr7[63:32] when propagating vmcs12->guest_dr7 to vmcs02, but ideally KVM would not rely on that behavior for correctness. Cc: Jim Mattson <jmattson@google.com> Cc: Krish Sadhukhan <krish.sadhukhan@oracle.com> Fixes: ecb697d10f70 ("KVM: nVMX: Check GUEST_DR7 on vmentry of nested guests") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/x86.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 2d2ff855773b..3624665acee4 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -357,7 +357,7 @@ static inline bool kvm_pat_valid(u64 data)
return (data | ((data & 0x0202020202020202ull) << 1)) == data;
}
-static inline bool kvm_dr7_valid(unsigned long data)
+static inline bool kvm_dr7_valid(u64 data)
{
/* Bits [63:32] are reserved */
return !(data >> 32);