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Subject[PATCH 02/12] KVM: x86: introduce num_emulated_msrs
Date
We will want to filter away MSR_IA32_SMBASE from the emulated_msrs if
the host CPU does not support SMM virtualization. Introduce the
logic to do that, and also move paravirt MSRs to emulated_msrs for
simplicity and to get rid of KVM_SAVE_MSRS_BEGIN.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/x86.c | 40 +++++++++++++++++++++++++++-------------
1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cdccbe1749a5..7b894f2523f6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -925,17 +925,11 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc);
*
* This list is modified at module load time to reflect the
* capabilities of the host cpu. This capabilities test skips MSRs that are
- * kvm-specific. Those are put in the beginning of the list.
+ * kvm-specific. Those are put in emulated_msrs; filtering of emulated_msrs
+ * may depend on host virtualization features rather than host cpu features.
*/

-#define KVM_SAVE_MSRS_BEGIN 12
static u32 msrs_to_save[] = {
- MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
- MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
- HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
- HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
- HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
- MSR_KVM_PV_EOI_EN,
MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
MSR_STAR,
#ifdef CONFIG_X86_64
@@ -947,7 +941,14 @@ static u32 msrs_to_save[] = {

static unsigned num_msrs_to_save;

-static const u32 emulated_msrs[] = {
+static u32 emulated_msrs[] = {
+ MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
+ MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
+ HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
+ HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
+ HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
+ MSR_KVM_PV_EOI_EN,
+
MSR_IA32_TSC_ADJUST,
MSR_IA32_TSCDEADLINE,
MSR_IA32_MISC_ENABLE,
@@ -955,6 +956,8 @@ static const u32 emulated_msrs[] = {
MSR_IA32_MCG_CTL,
};

+static unsigned num_emulated_msrs;
+
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
{
if (efer & efer_reserved_bits)
@@ -2864,7 +2867,7 @@ long kvm_arch_dev_ioctl(struct file *filp,
if (copy_from_user(&msr_list, user_msr_list, sizeof msr_list))
goto out;
n = msr_list.nmsrs;
- msr_list.nmsrs = num_msrs_to_save + ARRAY_SIZE(emulated_msrs);
+ msr_list.nmsrs = num_msrs_to_save + num_emulated_msrs;
if (copy_to_user(user_msr_list, &msr_list, sizeof msr_list))
goto out;
r = -E2BIG;
@@ -2876,7 +2879,7 @@ long kvm_arch_dev_ioctl(struct file *filp,
goto out;
if (copy_to_user(user_msr_list->indices + num_msrs_to_save,
&emulated_msrs,
- ARRAY_SIZE(emulated_msrs) * sizeof(u32)))
+ num_emulated_msrs * sizeof(u32)))
goto out;
r = 0;
break;
@@ -4142,8 +4145,7 @@ static void kvm_init_msr_list(void)
u32 dummy[2];
unsigned i, j;

- /* skip the first msrs in the list. KVM-specific */
- for (i = j = KVM_SAVE_MSRS_BEGIN; i < ARRAY_SIZE(msrs_to_save); i++) {
+ for (i = j = 0; i < ARRAY_SIZE(msrs_to_save); i++) {
if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0)
continue;

@@ -4168,6 +4170,18 @@ static void kvm_init_msr_list(void)
j++;
}
num_msrs_to_save = j;
+
+ for (i = j = 0; i < ARRAY_SIZE(emulated_msrs); i++) {
+ switch (emulated_msrs[i]) {
+ default:
+ break;
+ }
+
+ if (j < i)
+ emulated_msrs[j] = emulated_msrs[i];
+ j++;
+ }
+ num_emulated_msrs = j;
}

static int vcpu_mmio_write(struct kvm_vcpu *vcpu, gpa_t addr, int len,
--
1.8.3.1



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