From 112dad69d723a68205f255dd46d78871b5c5a8ca Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Fri, 8 Jul 2016 16:01:37 +0100 Subject: target-i386: Mask mtrr mask based on CPU physical address limits The CPU GPs if we try and set a bit in a variable MTRR mask above the limit of physical address bits on the host. We hit this when loading a migration from a host with a larger physical address limit than our destination (e.g. a Xeon->i7 of same generation) but previously used to get away with it until 48e1a45 started checking that msr writes actually worked. It seems in our case the GP probably comes from KVM emulating that GP. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Eduardo Habkost Signed-off-by: Eduardo Habkost --- target-i386/kvm.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'target-i386/kvm.c') diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 93275231ec..2f1cc62795 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -1716,6 +1716,8 @@ static int kvm_put_msrs(X86CPU *cpu, int level) } } if (has_msr_mtrr) { + uint64_t phys_mask = MAKE_64BIT_MASK(0, cpu->phys_bits); + kvm_msr_entry_add(cpu, MSR_MTRRdefType, env->mtrr_deftype); kvm_msr_entry_add(cpu, MSR_MTRRfix64K_00000, env->mtrr_fixed[0]); kvm_msr_entry_add(cpu, MSR_MTRRfix16K_80000, env->mtrr_fixed[1]); @@ -1729,10 +1731,15 @@ static int kvm_put_msrs(X86CPU *cpu, int level) kvm_msr_entry_add(cpu, MSR_MTRRfix4K_F0000, env->mtrr_fixed[9]); kvm_msr_entry_add(cpu, MSR_MTRRfix4K_F8000, env->mtrr_fixed[10]); for (i = 0; i < MSR_MTRRcap_VCNT; i++) { + /* The CPU GPs if we write to a bit above the physical limit of + * the host CPU (and KVM emulates that) + */ + uint64_t mask = env->mtrr_var[i].mask; + mask &= phys_mask; + kvm_msr_entry_add(cpu, MSR_MTRRphysBase(i), env->mtrr_var[i].base); - kvm_msr_entry_add(cpu, MSR_MTRRphysMask(i), - env->mtrr_var[i].mask); + kvm_msr_entry_add(cpu, MSR_MTRRphysMask(i), mask); } } -- cgit v1.2.3