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authorPaolo Bonzini <pbonzini@redhat.com>2015-12-14 16:57:31 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2015-12-22 15:28:56 +0100
commitfa7c4ebd5ae0c22f9908436303106a9ffcf0cf42 (patch)
tree62ffda16edba07ab21f4a7b486a00472ac174869
parenta7f2d7865720ff13d5b0f2a3bb1fd80dc3d7a73f (diff)
downloadlinux-stericsson-fa7c4ebd5ae0c22f9908436303106a9ffcf0cf42.tar.gz
KVM: MTRR: observe maxphyaddr from guest CPUID, not host
Conversion of MTRRs to ranges used the maxphyaddr from the boot CPU. This is wrong, because var_mtrr_range's mask variable then is discontiguous (like FF00FFFF000, where the first run of 0s corresponds to the bits between host and guest maxphyaddr). Instead always set up the masks to be full 64-bit values---we know that the reserved bits at the top are zero, and we can restore them when reading the MSR. This way var_mtrr_range gets a mask that just works. Fixes: a13842dc668b40daef4327294a6d3bdc8bd30276 Cc: qemu-stable@nongnu.org Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107561 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/mtrr.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
index adc54e1d40a9..7747b6d716fa 100644
--- a/arch/x86/kvm/mtrr.c
+++ b/arch/x86/kvm/mtrr.c
@@ -300,7 +300,6 @@ static void var_mtrr_range(struct kvm_mtrr_range *range, u64 *start, u64 *end)
*start = range->base & PAGE_MASK;
mask = range->mask & PAGE_MASK;
- mask |= ~0ULL << boot_cpu_data.x86_phys_bits;
/* This cannot overflow because writing to the reserved bits of
* variable MTRRs causes a #GP.
@@ -356,10 +355,14 @@ static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
if (var_mtrr_range_is_valid(cur))
list_del(&mtrr_state->var_ranges[index].node);
+ /* Extend the mask with all 1 bits to the left, since those
+ * bits must implicitly be 0. The bits are then cleared
+ * when reading them.
+ */
if (!is_mtrr_mask)
cur->base = data;
else
- cur->mask = data;
+ cur->mask = data | (-1LL << cpuid_maxphyaddr(vcpu));
/* add it to the list if it's enabled. */
if (var_mtrr_range_is_valid(cur)) {
@@ -426,6 +429,8 @@ int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
*pdata = vcpu->arch.mtrr_state.var_ranges[index].base;
else
*pdata = vcpu->arch.mtrr_state.var_ranges[index].mask;
+
+ *pdata &= (1ULL << cpuid_maxphyaddr(vcpu)) - 1;
}
return 0;