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authorDr. David Alan Gilbert <dgilbert@redhat.com>2016-07-08 16:01:37 +0100
committerEduardo Habkost <ehabkost@redhat.com>2016-07-20 11:58:43 -0300
commit112dad69d723a68205f255dd46d78871b5c5a8ca (patch)
tree3e0ce08aef30f30a89da841b0f66a9f9ecd9a4bb
parentaf45907a132857cfd47acc998bf5f7c26cd13071 (diff)
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 <dgilbert@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
-rw-r--r--target-i386/kvm.c11
1 files changed, 9 insertions, 2 deletions
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);
}
}