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Date: Tue, 16 Jan 2018 17:52:24 +0100
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH 2/3] KVM: VMX: use same MSR bitmaps for 32-/64-bit modes
KVM has a small optimization where it doesn't save/restore
MSR_KERNEL_GS_BASE if the guest is in 32-bit mode. However, this
complicates the code noticeably by doubling the number of possible MSR
bitmaps. In addition, pt_disable_intercept_for_msr was only updating the
"basic" MSR bitmap, because x2apic and x2apic_apicv are memcpy'd just
once in hardware_setup.
In order to simplify the upcoming introduction of per-VCPU bitmaps,
remove the long-mode bitmaps set.
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
arch/x86/kvm/vmx.c | 95 +++++++++++++++++-------------------------------------
1 file changed, 29 insertions(+), 66 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d81fd4a87f2b..d8057fac336a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -913,12 +913,9 @@ static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock);
enum {
- VMX_MSR_BITMAP_LEGACY,
- VMX_MSR_BITMAP_LONGMODE,
- VMX_MSR_BITMAP_LEGACY_X2APIC_APICV,
- VMX_MSR_BITMAP_LONGMODE_X2APIC_APICV,
- VMX_MSR_BITMAP_LEGACY_X2APIC,
- VMX_MSR_BITMAP_LONGMODE_X2APIC,
+ VMX_MSR_BITMAP,
+ VMX_MSR_BITMAP_X2APIC_APICV,
+ VMX_MSR_BITMAP_X2APIC,
VMX_VMREAD_BITMAP,
VMX_VMWRITE_BITMAP,
VMX_BITMAP_NR
@@ -926,12 +923,9 @@ enum {
static unsigned long *vmx_bitmap[VMX_BITMAP_NR];
-#define vmx_msr_bitmap_legacy (vmx_bitmap[VMX_MSR_BITMAP_LEGACY])
-#define vmx_msr_bitmap_longmode (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE])
-#define vmx_msr_bitmap_legacy_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC_APICV])
-#define vmx_msr_bitmap_longmode_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE_X2APIC_APICV])
-#define vmx_msr_bitmap_legacy_x2apic (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC])
-#define vmx_msr_bitmap_longmode_x2apic (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE_X2APIC])
+#define vmx_msr_bitmap (vmx_bitmap[VMX_MSR_BITMAP])
+#define vmx_msr_bitmap_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_X2APIC_APICV])
+#define vmx_msr_bitmap_x2apic (vmx_bitmap[VMX_MSR_BITMAP_X2APIC])
#define vmx_vmread_bitmap (vmx_bitmap[VMX_VMREAD_BITMAP])
#define vmx_vmwrite_bitmap (vmx_bitmap[VMX_VMWRITE_BITMAP])
@@ -2119,8 +2113,7 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
#ifdef CONFIG_X86_64
rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
- if (is_long_mode(&vmx->vcpu))
- wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
+ wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
#endif
if (boot_cpu_has(X86_FEATURE_MPX))
rdmsrl(MSR_IA32_BNDCFGS, vmx->host_state.msr_host_bndcfgs);
@@ -2138,8 +2131,7 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx)
++vmx->vcpu.stat.host_state_reload;
vmx->host_state.loaded = 0;
#ifdef CONFIG_X86_64
- if (is_long_mode(&vmx->vcpu))
- rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
+ rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
#endif
if (vmx->host_state.gs_ldt_reload_needed) {
kvm_load_ldt(vmx->host_state.ldt_sel);
@@ -2541,22 +2533,12 @@ static void vmx_set_msr_bitmap(struct kvm_vcpu *vcpu)
else if (cpu_has_secondary_exec_ctrls() &&
(vmcs_read32(SECONDARY_VM_EXEC_CONTROL) &
SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
- if (enable_apicv && kvm_vcpu_apicv_active(vcpu)) {
- if (is_long_mode(vcpu))
- msr_bitmap = vmx_msr_bitmap_longmode_x2apic_apicv;
- else
- msr_bitmap = vmx_msr_bitmap_legacy_x2apic_apicv;
- } else {
- if (is_long_mode(vcpu))
- msr_bitmap = vmx_msr_bitmap_longmode_x2apic;
- else
- msr_bitmap = vmx_msr_bitmap_legacy_x2apic;
- }
- } else {
- if (is_long_mode(vcpu))
- msr_bitmap = vmx_msr_bitmap_longmode;
+ if (enable_apicv && kvm_vcpu_apicv_active(vcpu))
+ msr_bitmap = vmx_msr_bitmap_x2apic_apicv;
else
- msr_bitmap = vmx_msr_bitmap_legacy;
+ msr_bitmap = vmx_msr_bitmap_x2apic;
+ } else {
+ msr_bitmap = vmx_msr_bitmap;
}
vmcs_write64(MSR_BITMAP, __pa(msr_bitmap));
@@ -5014,21 +4996,15 @@ static void nested_vmx_disable_intercept_for_msr(unsigned long *msr_bitmap_l1,
}
}
-static void vmx_disable_intercept_for_msr(u32 msr, bool longmode_only)
+static void vmx_disable_intercept_for_msr(u32 msr)
{
- if (!longmode_only)
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy,
- msr, MSR_TYPE_R | MSR_TYPE_W);
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode,
+ __vmx_disable_intercept_for_msr(vmx_msr_bitmap,
msr, MSR_TYPE_R | MSR_TYPE_W);
}
-static void vmx_enable_intercept_for_msr(u32 msr, bool longmode_only)
+static void vmx_enable_intercept_for_msr(u32 msr)
{
- if (!longmode_only)
- __vmx_enable_intercept_for_msr(vmx_msr_bitmap_legacy,
- msr, MSR_TYPE_R | MSR_TYPE_W);
- __vmx_enable_intercept_for_msr(vmx_msr_bitmap_longmode,
+ __vmx_enable_intercept_for_msr(vmx_msr_bitmap,
msr, MSR_TYPE_R | MSR_TYPE_W);
}
@@ -5036,15 +5012,9 @@ static void vmx_enable_intercept_for_msr(u32 msr, bool longmode_only)
static void vmx_disable_intercept_msr_x2apic(u32 msr, int type, bool apicv_only)
{
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic_apicv,
- msr, type);
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic_apicv,
- msr, type);
+ __vmx_disable_intercept_for_msr(vmx_msr_bitmap_x2apic_apicv, msr, type);
if (!apicv_only) {
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic,
- msr, type);
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic,
- msr, type);
+ __vmx_disable_intercept_for_msr(vmx_msr_bitmap_x2apic, msr, type);
}
}
@@ -5488,7 +5458,7 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
vmcs_write64(VMWRITE_BITMAP, __pa(vmx_vmwrite_bitmap));
}
if (cpu_has_vmx_msr_bitmap())
- vmcs_write64(MSR_BITMAP, __pa(vmx_msr_bitmap_legacy));
+ vmcs_write64(MSR_BITMAP, __pa(vmx_msr_bitmap));
vmcs_write64(VMCS_LINK_POINTER, -1ull); /* 22.3.1.5 */
@@ -6794,8 +6764,7 @@ static __init int hardware_setup(void)
memset(vmx_vmread_bitmap, 0xff, PAGE_SIZE);
memset(vmx_vmwrite_bitmap, 0xff, PAGE_SIZE);
- memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE);
- memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE);
+ memset(vmx_msr_bitmap, 0xff, PAGE_SIZE);
if (setup_vmcs_config(&vmcs_config) < 0) {
r = -EIO;
@@ -6860,21 +6829,15 @@ static __init int hardware_setup(void)
kvm_tsc_scaling_ratio_frac_bits = 48;
}
- vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
- vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
- vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
- vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false);
- vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
- vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
+ vmx_disable_intercept_for_msr(MSR_FS_BASE);
+ vmx_disable_intercept_for_msr(MSR_GS_BASE);
+ vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE);
+ vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS);
+ vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP);
+ vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP);
- memcpy(vmx_msr_bitmap_legacy_x2apic_apicv,
- vmx_msr_bitmap_legacy, PAGE_SIZE);
- memcpy(vmx_msr_bitmap_longmode_x2apic_apicv,
- vmx_msr_bitmap_longmode, PAGE_SIZE);
- memcpy(vmx_msr_bitmap_legacy_x2apic,
- vmx_msr_bitmap_legacy, PAGE_SIZE);
- memcpy(vmx_msr_bitmap_longmode_x2apic,
- vmx_msr_bitmap_longmode, PAGE_SIZE);
+ memcpy(vmx_msr_bitmap_x2apic_apicv, vmx_msr_bitmap, PAGE_SIZE);
+ memcpy(vmx_msr_bitmap_x2apic, vmx_msr_bitmap, PAGE_SIZE);
set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
--
1.8.3.1
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