Il 10/04/2014 16:12, Marcelo Tosatti ha scritto:
On Tue, Apr 01, 2014 at 05:46:34PM +0800, Feng Wu wrote:
This patch adds SMAP handling logic when setting CR4 for guests
Thanks a lot to Paolo Bonzini for his suggestion to use the branchless
way to detect SMAP violation.
Signed-off-by: Feng Wu <feng...@intel.com>
@@ -110,10 +118,30 @@ static inline bool is_write_protection(struct kvm_vcpu
*vcpu)
* Will a fault with a given page-fault error code (pfec) cause a permission
* fault with the given access (in ACC_* format)?
*/
-static inline bool permission_fault(struct kvm_mmu *mmu, unsigned pte_access,
- unsigned pfec)
+static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+ unsigned pte_access, unsigned pfec)
{
- return (mmu->permissions[pfec >> 1] >> pte_access) & 1;
+ int cpl = kvm_x86_ops->get_cpl(vcpu);
+ unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);
Some branches added here (can't think of anything useful to avoid them).
Yeah, but most of them should be well predicted.
Paolo
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