diff options
author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-01-24 15:07:22 -0800 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-02-05 15:17:45 +0100 |
commit | 9b5e85320fcc3af20ce0397b2c6363b6ee5815b6 (patch) | |
tree | 3fe4822037bf20c2c43dbdd3f5713622e73a2756 /arch | |
parent | 8171cd68806bd2fc28ef688e32fb2a3b3deb04e5 (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.h | 2 |
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); |