Currently, if L1 enables MSR_BITMAP, we will emulate this feature,
all of L2's msr access is intercepted by L0. Since many features
like virtualize x2apic mode has a complicated logic and it is
difficult for us to emulate, we should use hardware and merge
the bitmap.
This patch introduces nested_vmx_merge_msr_bitmap for future use.
Signed-off-by: Wincy Van <fanwenyi0529@xxxxxxxxx>
---
arch/x86/kvm/vmx.c | 77 ++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 66 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 81152a0..4108676 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -805,6 +805,7 @@ static unsigned long *vmx_msr_bitmap_legacy;
static unsigned long *vmx_msr_bitmap_longmode;
static unsigned long *vmx_msr_bitmap_legacy_x2apic;
static unsigned long *vmx_msr_bitmap_longmode_x2apic;
+static unsigned long *vmx_msr_bitmap_nested;
static unsigned long *vmx_vmread_bitmap;
static unsigned long *vmx_vmwrite_bitmap;
@@ -5828,13 +5829,21 @@ static __init int hardware_setup(void)
(unsigned long *)__get_free_page(GFP_KERNEL);
if (!vmx_msr_bitmap_longmode_x2apic)
goto out4;
+
+ if (nested) {
+ vmx_msr_bitmap_nested =
+ (unsigned long *)__get_free_page(GFP_KERNEL);
+ if (!vmx_msr_bitmap_nested)
+ goto out5;
+ }
+
vmx_vmread_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
if (!vmx_vmread_bitmap)
- goto out5;
+ goto out6;
vmx_vmwrite_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
if (!vmx_vmwrite_bitmap)
- goto out6;
+ goto out7;
memset(vmx_vmread_bitmap, 0xff, PAGE_SIZE);
memset(vmx_vmwrite_bitmap, 0xff, PAGE_SIZE);
@@ -5850,10 +5859,12 @@ static __init int hardware_setup(void)
memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE);
memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE);
+ if (nested)
+ memset(vmx_msr_bitmap_nested, 0xff, PAGE_SIZE);
if (setup_vmcs_config(&vmcs_config) < 0) {
r = -EIO;
- goto out7;
+ goto out8;
}
if (boot_cpu_has(X86_FEATURE_NX))
@@ -5974,10 +5985,13 @@ static __init int hardware_setup(void)
return alloc_kvm_area();
-out7:
+out8:
free_page((unsigned long)vmx_vmwrite_bitmap);
-out6:
+out7:
free_page((unsigned long)vmx_vmread_bitmap);
+out6:
+ if (nested)
+ free_page((unsigned long)vmx_msr_bitmap_nested);
out5:
free_page((unsigned long)vmx_msr_bitmap_longmode_x2apic);
out4:
@@ -6004,6 +6018,8 @@ static __exit void hardware_unsetup(void)
free_page((unsigned long)vmx_io_bitmap_a);
free_page((unsigned long)vmx_vmwrite_bitmap);
free_page((unsigned long)vmx_vmread_bitmap);
+ if (nested)
+ free_page((unsigned long)vmx_msr_bitmap_nested);
free_kvm_area();
}
@@ -8468,6 +8484,38 @@ static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu)
ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL);
}
+static int nested_vmx_check_msr_bitmap_controls(struct kvm_vcpu *vcpu,
+ struct vmcs12 *vmcs12)
+{
+ int maxphyaddr;
+ u64 addr;
+
+ if (!nested_cpu_has(vmcs12, CPU_BASED_USE_MSR_BITMAPS))
+ return 0;
+
+ if (vmcs12_read_any(vcpu, MSR_BITMAP, &addr)) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+ maxphyaddr = cpuid_maxphyaddr(vcpu);
+
+ if (!PAGE_ALIGNED(vmcs12->msr_bitmap) ||
+ ((addr + PAGE_SIZE) >> maxphyaddr))
+ return -EINVAL;
+
+ return 0;
+}
+
+/*
+ * Merge L0's and L1's MSR bitmap, return false to indicate that
+ * we do not use the hardware.
+ */
+static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
+ struct vmcs12 *vmcs12)
+{
+ return false;
+}
+
static int nested_vmx_check_msr_switch(struct kvm_vcpu *vcpu,
unsigned long count_field,
unsigned long addr_field,
@@ -8800,11 +8848,17 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
vmcs_write32(TPR_THRESHOLD, vmcs12->tpr_threshold);
}
+ if (cpu_has_vmx_msr_bitmap() &&
+ exec_control & CPU_BASED_USE_MSR_BITMAPS &&
+ nested_vmx_merge_msr_bitmap(vcpu, vmcs12)) {
+ vmcs_write64(MSR_BITMAP, __pa(vmx_msr_bitmap_nested));
+ } else
+ exec_control &= ~CPU_BASED_USE_MSR_BITMAPS;
+
/*
- * Merging of IO and MSR bitmaps not currently supported.
+ * Merging of IO bitmap not currently supported.
* Rather, exit every time.
*/
- exec_control &= ~CPU_BASED_USE_MSR_BITMAPS;
exec_control &= ~CPU_BASED_USE_IO_BITMAPS;
exec_control |= CPU_BASED_UNCOND_IO_EXITING;
@@ -8955,15 +9009,13 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
return 1;
}
- if ((vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_MSR_BITMAPS) &&
- !PAGE_ALIGNED(vmcs12->msr_bitmap)) {
+ if (!nested_get_vmcs12_pages(vcpu, vmcs12)) {
/*TODO: Also verify bits beyond physical address width are 0*/
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
}
- if (!nested_get_vmcs12_pages(vcpu, vmcs12)) {
- /*TODO: Also verify bits beyond physical address width are 0*/
+ if (nested_vmx_check_msr_bitmap_controls(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
return 1;
}
@@ -9519,6 +9571,9 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
kvm_set_dr(vcpu, 7, 0x400);
vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
+ if (cpu_has_vmx_msr_bitmap())
+ vmx_set_msr_bitmap(vcpu);
+
if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr,
vmcs12->vm_exit_msr_load_count))
nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_MSR_FAIL);
--
1.7.1
--
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