[PATCH 10/10] KVM: selftests: add tests for shadow VMCS save/restore

From: Paolo Bonzini
Date: Sat Jul 28 2018 - 19:10:34 EST


This includes setting up the shadow VMCS and the secondary execution
controls in lib/vmx.c.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
tools/testing/selftests/kvm/include/vmx.h | 12 +++++++++++
tools/testing/selftests/kvm/lib/vmx.c | 33 +++++++++++++++++++++++++++---
tools/testing/selftests/kvm/state_test.c | 34 +++++++++++++++++++++++++++++--
3 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/vmx.h b/tools/testing/selftests/kvm/include/vmx.h
index 2b37f9b6f7df..02cdecf9560c 100644
--- a/tools/testing/selftests/kvm/include/vmx.h
+++ b/tools/testing/selftests/kvm/include/vmx.h
@@ -530,6 +530,18 @@ struct vmx_pages {
void *msr_hva;
uint64_t msr_gpa;
void *msr;
+
+ void *shadow_vmcs_hva;
+ uint64_t shadow_vmcs_gpa;
+ void *shadow_vmcs;
+
+ void *vmread_hva;
+ uint64_t vmread_gpa;
+ void *vmread;
+
+ void *vmwrite_hva;
+ uint64_t vmwrite_gpa;
+ void *vmwrite;
};

struct vmx_pages *vcpu_alloc_vmx(struct kvm_vm *vm, vm_vaddr_t *p_vmx_gva);
diff --git a/tools/testing/selftests/kvm/lib/vmx.c b/tools/testing/selftests/kvm/lib/vmx.c
index 5701e52a33ed..b987c3c970eb 100644
--- a/tools/testing/selftests/kvm/lib/vmx.c
+++ b/tools/testing/selftests/kvm/lib/vmx.c
@@ -44,6 +44,23 @@ struct vmx_pages *
vmx->msr = (void *)vm_vaddr_alloc(vm, getpagesize(), 0x10000, 0, 0);
vmx->msr_hva = addr_gva2hva(vm, (uintptr_t)vmx->msr);
vmx->msr_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->msr);
+ memset(vmx->msr_hva, 0, getpagesize());
+
+ /* Setup of a region of guest memory for the shadow VMCS. */
+ vmx->shadow_vmcs = (void *)vm_vaddr_alloc(vm, getpagesize(), 0x10000, 0, 0);
+ vmx->shadow_vmcs_hva = addr_gva2hva(vm, (uintptr_t)vmx->shadow_vmcs);
+ vmx->shadow_vmcs_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->shadow_vmcs);
+
+ /* Setup of a region of guest memory for the VMREAD and VMWRITE bitmaps. */
+ vmx->vmread = (void *)vm_vaddr_alloc(vm, getpagesize(), 0x10000, 0, 0);
+ vmx->vmread_hva = addr_gva2hva(vm, (uintptr_t)vmx->vmread);
+ vmx->vmread_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->vmread);
+ memset(vmx->vmread_hva, 0, getpagesize());
+
+ vmx->vmwrite = (void *)vm_vaddr_alloc(vm, getpagesize(), 0x10000, 0, 0);
+ vmx->vmwrite_hva = addr_gva2hva(vm, (uintptr_t)vmx->vmwrite);
+ vmx->vmwrite_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->vmwrite);
+ memset(vmx->vmwrite_hva, 0, getpagesize());

*p_vmx_gva = vmx_gva;
return vmx;
@@ -98,6 +115,11 @@ bool prepare_for_vmx_operation(struct vmx_pages *vmx)
if (vmptrld(vmx->vmcs_gpa))
return false;

+ /* Setup shadow VMCS, do not load it yet. */
+ *(uint32_t *)(vmx->shadow_vmcs) = vmcs_revision() | 0x80000000ul;
+ if (vmclear(vmx->shadow_vmcs_gpa))
+ return false;
+
return true;
}

@@ -109,8 +131,12 @@ static inline void init_vmcs_control_fields(struct vmx_pages *vmx)
vmwrite(VIRTUAL_PROCESSOR_ID, 0);
vmwrite(POSTED_INTR_NV, 0);

- vmwrite(PIN_BASED_VM_EXEC_CONTROL, rdmsr(MSR_IA32_VMX_PINBASED_CTLS));
- vmwrite(CPU_BASED_VM_EXEC_CONTROL, rdmsr(MSR_IA32_VMX_PROCBASED_CTLS));
+ vmwrite(PIN_BASED_VM_EXEC_CONTROL, rdmsr(MSR_IA32_VMX_TRUE_PINBASED_CTLS));
+ if (!vmwrite(SECONDARY_VM_EXEC_CONTROL, 0))
+ vmwrite(CPU_BASED_VM_EXEC_CONTROL,
+ rdmsr(MSR_IA32_VMX_TRUE_PROCBASED_CTLS) | CPU_BASED_ACTIVATE_SECONDARY_CONTROLS);
+ else
+ vmwrite(CPU_BASED_VM_EXEC_CONTROL, rdmsr(MSR_IA32_VMX_TRUE_PROCBASED_CTLS));
vmwrite(EXCEPTION_BITMAP, 0);
vmwrite(PAGE_FAULT_ERROR_CODE_MASK, 0);
vmwrite(PAGE_FAULT_ERROR_CODE_MATCH, -1); /* Never match */
@@ -124,7 +150,6 @@ static inline void init_vmcs_control_fields(struct vmx_pages *vmx)
vmwrite(VM_ENTRY_MSR_LOAD_COUNT, 0);
vmwrite(VM_ENTRY_INTR_INFO_FIELD, 0);
vmwrite(TPR_THRESHOLD, 0);
- vmwrite(SECONDARY_VM_EXEC_CONTROL, 0);

vmwrite(CR0_GUEST_HOST_MASK, 0);
vmwrite(CR4_GUEST_HOST_MASK, 0);
@@ -132,6 +157,8 @@ static inline void init_vmcs_control_fields(struct vmx_pages *vmx)
vmwrite(CR4_READ_SHADOW, get_cr4());

vmwrite(MSR_BITMAP, vmx->msr_gpa);
+ vmwrite(VMREAD_BITMAP, vmx->vmread_gpa);
+ vmwrite(VMWRITE_BITMAP, vmx->vmwrite_gpa);
}

/*
diff --git a/tools/testing/selftests/kvm/state_test.c b/tools/testing/selftests/kvm/state_test.c
index 447da4f76b56..833319b06577 100644
--- a/tools/testing/selftests/kvm/state_test.c
+++ b/tools/testing/selftests/kvm/state_test.c
@@ -55,7 +55,15 @@ void l2_guest_code(void)
/* Exit to L1 */
vmcall();

- GUEST_SYNC(7);
+ /* L1 has now set up a shadow VMCS for us. */
+ GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
+ GUEST_SYNC(9);
+ GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
+ GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0fffee));
+ GUEST_SYNC(10);
+ GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0fffee);
+ GUEST_ASSERT(!vmwrite(GUEST_RIP, 0xc0ffffee));
+ GUEST_SYNC(11);

/* Done, exit to L1 and never come back. */
vmcall();
@@ -96,9 +104,31 @@ void l1_guest_code(struct vmx_pages *vmx_pages)

vmwrite(GUEST_RIP, vmreadz(GUEST_RIP) + 3);

+ vmwrite(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_SHADOW_VMCS);
+ vmwrite(VMCS_LINK_POINTER, vmx_pages->shadow_vmcs_gpa);
+
+ GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
+ GUEST_ASSERT(vmlaunch());
+ GUEST_SYNC(7);
+ GUEST_ASSERT(vmlaunch());
+ GUEST_ASSERT(vmresume());
+
+ vmwrite(GUEST_RIP, 0xc0ffee);
+ GUEST_SYNC(8);
+ GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffee);
+
+ GUEST_ASSERT(!vmptrld(vmx_pages->vmcs_gpa));
GUEST_ASSERT(!vmresume());
GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
- GUEST_SYNC(8);
+
+ GUEST_ASSERT(!vmptrld(vmx_pages->shadow_vmcs_gpa));
+ GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
+ GUEST_ASSERT(vmlaunch());
+ GUEST_ASSERT(vmresume());
+ GUEST_SYNC(12);
+ GUEST_ASSERT(vmreadz(GUEST_RIP) == 0xc0ffffee);
+ GUEST_ASSERT(vmlaunch());
+ GUEST_ASSERT(vmresume());
}

void guest_code(struct vmx_pages *vmx_pages)
--
1.8.3.1