@@ -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;
This is a note to let you know that I have just added a patch titled KVM: MTRR: observe maxphyaddr from guest CPUID, not host to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 23859850f2c3fd4f1f22acb9850fe2f619bb33f6 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini <pbonzini@redhat.com> Date: Mon, 14 Dec 2015 16:57:31 +0100 Subject: KVM: MTRR: observe maxphyaddr from guest CPUID, not host commit fa7c4ebd5ae0c22f9908436303106a9ffcf0cf42 upstream. 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 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=107561 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/x86/kvm/mtrr.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) -- 1.9.1