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kvm: nVMX: Refactor nested_get_vmcs12_pages()
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Perform the checks on vmcs12 state early, but defer the gpa->hpa lookups
until after prepare_vmcs02. Later, when we restore the checkpointed
state of a vCPU in guest mode, we will not be able to do the gpa->hpa
lookups when the restore is done.

Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Jim Mattson authored and Paolo Bonzini committed Feb 15, 2017
1 parent a8bc284 commit 6beb7bd
Showing 1 changed file with 69 additions and 69 deletions.
138 changes: 69 additions & 69 deletions arch/x86/kvm/vmx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9626,17 +9626,16 @@ static void vmx_inject_page_fault_nested(struct kvm_vcpu *vcpu,
kvm_inject_page_fault(vcpu, fault);
}

static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu,
static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12);

static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
int maxphyaddr = cpuid_maxphyaddr(vcpu);
u64 hpa;

if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {
if (!PAGE_ALIGNED(vmcs12->apic_access_addr) ||
vmcs12->apic_access_addr >> maxphyaddr)
return false;

/*
* Translate L1 physical address to host physical
* address for vmcs02. Keep the page pinned, so this
Expand All @@ -9647,59 +9646,80 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu,
nested_release_page(vmx->nested.apic_access_page);
vmx->nested.apic_access_page =
nested_get_page(vcpu, vmcs12->apic_access_addr);
/*
* If translation failed, no matter: This feature asks
* to exit when accessing the given address, and if it
* can never be accessed, this feature won't do
* anything anyway.
*/
if (vmx->nested.apic_access_page) {
hpa = page_to_phys(vmx->nested.apic_access_page);
vmcs_write64(APIC_ACCESS_ADDR, hpa);
} else {
vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL,
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES);
}
} else if (!(nested_cpu_has_virt_x2apic_mode(vmcs12)) &&
cpu_need_virtualize_apic_accesses(&vmx->vcpu)) {
vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL,
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES);
kvm_vcpu_reload_apic_access_page(vcpu);
}

if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) {
if (!PAGE_ALIGNED(vmcs12->virtual_apic_page_addr) ||
vmcs12->virtual_apic_page_addr >> maxphyaddr)
return false;

if (vmx->nested.virtual_apic_page) /* shouldn't happen */
nested_release_page(vmx->nested.virtual_apic_page);
vmx->nested.virtual_apic_page =
nested_get_page(vcpu, vmcs12->virtual_apic_page_addr);

/*
* Failing the vm entry is _not_ what the processor does
* but it's basically the only possibility we have.
* We could still enter the guest if CR8 load exits are
* enabled, CR8 store exits are enabled, and virtualize APIC
* access is disabled; in this case the processor would never
* use the TPR shadow and we could simply clear the bit from
* the execution control. But such a configuration is useless,
* so let's keep the code simple.
* If translation failed, VM entry will fail because
* prepare_vmcs02 set VIRTUAL_APIC_PAGE_ADDR to -1ull.
* Failing the vm entry is _not_ what the processor
* does but it's basically the only possibility we
* have. We could still enter the guest if CR8 load
* exits are enabled, CR8 store exits are enabled, and
* virtualize APIC access is disabled; in this case
* the processor would never use the TPR shadow and we
* could simply clear the bit from the execution
* control. But such a configuration is useless, so
* let's keep the code simple.
*/
if (!vmx->nested.virtual_apic_page)
return false;
if (vmx->nested.virtual_apic_page) {
hpa = page_to_phys(vmx->nested.virtual_apic_page);
vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, hpa);
}
}

if (nested_cpu_has_posted_intr(vmcs12)) {
if (!IS_ALIGNED(vmcs12->posted_intr_desc_addr, 64) ||
vmcs12->posted_intr_desc_addr >> maxphyaddr)
return false;

if (vmx->nested.pi_desc_page) { /* shouldn't happen */
kunmap(vmx->nested.pi_desc_page);
nested_release_page(vmx->nested.pi_desc_page);
}
vmx->nested.pi_desc_page =
nested_get_page(vcpu, vmcs12->posted_intr_desc_addr);
if (!vmx->nested.pi_desc_page)
return false;

vmx->nested.pi_desc =
(struct pi_desc *)kmap(vmx->nested.pi_desc_page);
if (!vmx->nested.pi_desc) {
nested_release_page_clean(vmx->nested.pi_desc_page);
return false;
return;
}
vmx->nested.pi_desc =
(struct pi_desc *)((void *)vmx->nested.pi_desc +
(unsigned long)(vmcs12->posted_intr_desc_addr &
(PAGE_SIZE - 1)));
vmcs_write64(POSTED_INTR_DESC_ADDR,
page_to_phys(vmx->nested.pi_desc_page) +
(unsigned long)(vmcs12->posted_intr_desc_addr &
(PAGE_SIZE - 1)));
}

return true;
if (cpu_has_vmx_msr_bitmap() &&
nested_cpu_has(vmcs12, CPU_BASED_USE_MSR_BITMAPS) &&
nested_vmx_merge_msr_bitmap(vcpu, vmcs12))
;
else
vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL,
CPU_BASED_USE_MSR_BITMAPS);
}

static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu)
Expand Down Expand Up @@ -10146,12 +10166,9 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
vmx->nested.posted_intr_nv = vmcs12->posted_intr_nv;
vmx->nested.pi_pending = false;
vmcs_write16(POSTED_INTR_NV, POSTED_INTR_VECTOR);
vmcs_write64(POSTED_INTR_DESC_ADDR,
page_to_phys(vmx->nested.pi_desc_page) +
(unsigned long)(vmcs12->posted_intr_desc_addr &
(PAGE_SIZE - 1)));
} else
} else {
exec_control &= ~PIN_BASED_POSTED_INTR;
}

vmcs_write32(PIN_BASED_VM_EXEC_CONTROL, exec_control);

Expand Down Expand Up @@ -10196,26 +10213,6 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
exec_control |= vmcs12->secondary_vm_exec_control;

if (exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES) {
/*
* If translation failed, no matter: This feature asks
* to exit when accessing the given address, and if it
* can never be accessed, this feature won't do
* anything anyway.
*/
if (!vmx->nested.apic_access_page)
exec_control &=
~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
else
vmcs_write64(APIC_ACCESS_ADDR,
page_to_phys(vmx->nested.apic_access_page));
} else if (!(nested_cpu_has_virt_x2apic_mode(vmcs12)) &&
cpu_need_virtualize_apic_accesses(&vmx->vcpu)) {
exec_control |=
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
kvm_vcpu_reload_apic_access_page(vcpu);
}

if (exec_control & SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY) {
vmcs_write64(EOI_EXIT_BITMAP0,
vmcs12->eoi_exit_bitmap0);
Expand All @@ -10230,6 +10227,15 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
}

nested_ept_enabled = (exec_control & SECONDARY_EXEC_ENABLE_EPT) != 0;

/*
* Write an illegal value to APIC_ACCESS_ADDR. Later,
* nested_get_vmcs12_pages will either fix it up or
* remove the VM execution control.
*/
if (exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)
vmcs_write64(APIC_ACCESS_ADDR, -1ull);

vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
}

Expand Down Expand Up @@ -10266,19 +10272,16 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
exec_control &= ~CPU_BASED_TPR_SHADOW;
exec_control |= vmcs12->cpu_based_vm_exec_control;

/*
* Write an illegal value to VIRTUAL_APIC_PAGE_ADDR. Later, if
* nested_get_vmcs12_pages can't fix it up, the illegal value
* will result in a VM entry failure.
*/
if (exec_control & CPU_BASED_TPR_SHADOW) {
vmcs_write64(VIRTUAL_APIC_PAGE_ADDR,
page_to_phys(vmx->nested.virtual_apic_page));
vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, -1ull);
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))
; /* MSR_BITMAP will be set by following vmx_set_efer. */
else
exec_control &= ~CPU_BASED_USE_MSR_BITMAPS;

/*
* Merging of IO bitmap not currently supported.
* Rather, exit every time.
Expand Down Expand Up @@ -10456,11 +10459,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
goto out;
}

if (!nested_get_vmcs12_pages(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
goto out;
}

if (nested_vmx_check_msr_bitmap_controls(vcpu, vmcs12)) {
nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
goto out;
Expand Down Expand Up @@ -10592,6 +10590,8 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
return 1;
}

nested_get_vmcs12_pages(vcpu, vmcs12);

msr_entry_idx = nested_vmx_load_msr(vcpu,
vmcs12->vm_entry_msr_load_addr,
vmcs12->vm_entry_msr_load_count);
Expand Down

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