Add a helper to query whether a variable MTRR MSR is a base versus as mask
MSR. Replace the unnecessarily complex math with a simple check on bit 0;
base MSRs are even, mask MSRs are odd.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mtrr.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
index 9fac1ec03463..f65ce4b3980f 100644
--- a/arch/x86/kvm/mtrr.c
+++ b/arch/x86/kvm/mtrr.c
@@ -25,6 +25,12 @@
#define IA32_MTRR_DEF_TYPE_FE (1ULL << 10)
#define IA32_MTRR_DEF_TYPE_TYPE_MASK (0xff)
+static bool is_mtrr_base_msr(unsigned int msr)
+{
+ /* MTRR base MSRs use even numbers, masks use odd numbers. */
+ return !(msr & 0x1);
+}
+
static bool msr_mtrr_valid(unsigned msr)
{
switch (msr) {
@@ -342,10 +348,9 @@ static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
struct kvm_mtrr_range *tmp, *cur;
- int index, is_mtrr_mask;
+ int index;
index = (msr - 0x200) / 2;
- is_mtrr_mask = msr - 0x200 - 2 * index;
cur = &mtrr_state->var_ranges[index];
/* remove the entry if it's in the list. */
@@ -356,7 +361,7 @@ static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
* Set all illegal GPA bits in the mask, since those bits must
* implicitly be 0. The bits are then cleared when reading them.
*/
- if (!is_mtrr_mask)
+ if (is_mtrr_base_msr(msr))
cur->base = data;
else
cur->mask = data | kvm_vcpu_reserved_gpa_bits_raw(vcpu);
@@ -418,11 +423,8 @@ int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
else if (msr == MSR_IA32_CR_PAT)
*pdata = vcpu->arch.pat;
else { /* Variable MTRRs */
- int is_mtrr_mask;
-
index = (msr - 0x200) / 2;
- is_mtrr_mask = msr - 0x200 - 2 * index;
- if (!is_mtrr_mask)
+ if (is_mtrr_base_msr(msr))
*pdata = vcpu->arch.mtrr_state.var_ranges[index].base;
else
*pdata = vcpu->arch.mtrr_state.var_ranges[index].mask;
--
2.40.1.606.ga4b1b128d6-goog
