From fd2752352bbc98850d83b5448a288d8991590317 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 29 Aug 2014 18:56:01 +0200 Subject: [PATCH] KVM: x86: use guest maxphyaddr to check MTRR values The check introduced in commit d7a2a246a1b5 (KVM: x86: #GP when attempts to write reserved bits of Variable Range MTRRs, 2014-08-19) will break if the guest maxphyaddr is higher than the host's (which sometimes happens depending on your hardware and how QEMU is configured). To fix this, use cpuid_maxphyaddr similar to how the APIC_BASE MSR does already. Reported-by: Jan Kiszka Tested-by: Jan Kiszka Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a375dfc..916e895 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1726,7 +1726,7 @@ static bool valid_mtrr_type(unsigned t) static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) { int i; - u64 mask = 0; + u64 mask; if (!msr_mtrr_valid(msr)) return false; @@ -1750,8 +1750,7 @@ static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) /* variable MTRRs */ WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR)); - for (i = 63; i > boot_cpu_data.x86_phys_bits; i--) - mask |= (1ULL << i); + mask = (~0ULL) << cpuid_maxphyaddr(vcpu); if ((msr & 1) == 0) { /* MTRR base */ if (!valid_mtrr_type(data & 0xff)) -- 2.7.4