diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c index 5303e0e96f..5c43ec989a 100644 --- a/xen/arch/x86/xstate.c +++ b/xen/arch/x86/xstate.c @@ -717,12 +717,32 @@ int handle_xsetbv(u32 index, u64 new_bv) if ( index != XCR_XFEATURE_ENABLED_MASK ) return -EOPNOTSUPP; - if ( (new_bv & ~xcr0_max) || - (new_bv & ~xfeature_mask) || !valid_xcr0(new_bv) ) + /* + * The CPUID logic shouldn't be able to hand out an XCR0 exceeding Xen's + * maximum features, but keep the check for robustness. + */ + if ( unlikely(xcr0_max & ~xfeature_mask) ) + { + gprintk(XENLOG_ERR, + "xcr0_max %016" PRIx64 " exceeds hardware max %016" PRIx64 "\n", + xcr0_max, xfeature_mask); + domain_crash(curr->domain); + + return -EINVAL; + } + + if ( (new_bv & ~xcr0_max) || !valid_xcr0(new_bv) ) return -EINVAL; - if ( !set_xcr0(new_bv) ) + /* By this point, new_bv really should be accepted by hardware. */ + if ( unlikely(!set_xcr0(new_bv)) ) + { + gprintk(XENLOG_ERR, "new_bv %016" PRIx64 " rejected by hardware\n", + new_bv); + domain_crash(curr->domain); + return -EFAULT; + } mask = new_bv & ~curr->arch.xcr0_accum; curr->arch.xcr0 = new_bv;