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Diffstat (limited to 'arch/x86/kvm/mtrr.c')
-rw-r--r--arch/x86/kvm/mtrr.c25
1 files changed, 19 insertions, 6 deletions
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
index 9e8bf1357..3f8c73211 100644
--- a/arch/x86/kvm/mtrr.c
+++ b/arch/x86/kvm/mtrr.c
@@ -120,14 +120,22 @@ static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state)
return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK;
}
-static u8 mtrr_disabled_type(void)
+static u8 mtrr_disabled_type(struct kvm_vcpu *vcpu)
{
/*
* Intel SDM 11.11.2.2: all MTRRs are disabled when
* IA32_MTRR_DEF_TYPE.E bit is cleared, and the UC
* memory type is applied to all of physical memory.
+ *
+ * However, virtual machines can be run with CPUID such that
+ * there are no MTRRs. In that case, the firmware will never
+ * enable MTRRs and it is obviously undesirable to run the
+ * guest entirely with UC memory and we use WB.
*/
- return MTRR_TYPE_UNCACHABLE;
+ if (guest_cpuid_has_mtrr(vcpu))
+ return MTRR_TYPE_UNCACHABLE;
+ else
+ return MTRR_TYPE_WRBACK;
}
/*
@@ -267,7 +275,7 @@ static int fixed_mtrr_addr_to_seg(u64 addr)
for (seg = 0; seg < seg_num; seg++) {
mtrr_seg = &fixed_seg_table[seg];
- if (mtrr_seg->start >= addr && addr < mtrr_seg->end)
+ if (mtrr_seg->start <= addr && addr < mtrr_seg->end)
return seg;
}
@@ -300,7 +308,6 @@ 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 +363,14 @@ 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 +437,8 @@ 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;
@@ -670,7 +683,7 @@ u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
}
if (iter.mtrr_disabled)
- return mtrr_disabled_type();
+ return mtrr_disabled_type(vcpu);
/* not contained in any MTRRs. */
if (type == -1)