[PATCH v1 22/23] KVM: selftests: Add a new VM guest mode to run user level code

Xin Li
2023-11-08T19:00:32Z

Add a new VM guest mode VM_MODE_PXXV48_4K_USER to set the user bit of
guest page table entries, thus allow user level code to run in guests.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
.../testing/selftests/kvm/include/kvm_util_base.h | 1 +
tools/testing/selftests/kvm/lib/kvm_util.c | 5 ++++-
.../testing/selftests/kvm/lib/x86_64/processor.c | 15 ++++++++++-----
tools/testing/selftests/kvm/lib/x86_64/vmx.c | 4 ++--
4 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index a18db6a7b3cf..1d2922447978 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -185,6 +185,7 @@ enum vm_guest_mode {
VM_MODE_P36V48_16K,
VM_MODE_P36V48_64K,
VM_MODE_P36V47_16K,
+ VM_MODE_PXXV48_4K_USER, /* For 48bits VA but ANY bits PA with USER bit set */
NUM_VM_MODES,
};

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 7a8af1821f5d..36f2acb378b6 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -162,6 +162,7 @@ const char *vm_guest_mode_string(uint32_t i)
[VM_MODE_P36V48_16K] = "PA-bits:36, VA-bits:48, 16K pages",
[VM_MODE_P36V48_64K] = "PA-bits:36, VA-bits:48, 64K pages",
[VM_MODE_P36V47_16K] = "PA-bits:36, VA-bits:47, 16K pages",
+ [VM_MODE_PXXV48_4K_USER] = "PA-bits:ANY, VA-bits:48, 4K user pages",
};
_Static_assert(sizeof(strings)/sizeof(char *) == NUM_VM_MODES,
"Missing new mode strings?");
@@ -187,6 +188,7 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
[VM_MODE_P36V48_16K] = { 36, 48, 0x4000, 14 },
[VM_MODE_P36V48_64K] = { 36, 48, 0x10000, 16 },
[VM_MODE_P36V47_16K] = { 36, 47, 0x4000, 14 },
+ [VM_MODE_PXXV48_4K_USER] = { 0, 0, 0x1000, 12 },
};
_Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
"Missing new mode params?");
@@ -260,6 +262,7 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode)
vm->pgtable_levels = 3;
break;
case VM_MODE_PXXV48_4K:
+ case VM_MODE_PXXV48_4K_USER:
#ifdef __x86_64__
kvm_get_cpu_address_width(&vm->pa_bits, &vm->va_bits);
/*
@@ -275,7 +278,7 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode)
vm->pgtable_levels = 4;
vm->va_bits = 48;
#else
- TEST_FAIL("VM_MODE_PXXV48_4K not supported on non-x86 platforms");
+ TEST_FAIL("VM_MODE_PXXV48_4K(_USER) not supported on non-x86 platforms");
#endif
break;
case VM_MODE_P47V64_4K:
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index d8288374078e..a8e60641df53 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -124,8 +124,8 @@ bool kvm_is_tdp_enabled(void)

void virt_arch_pgd_alloc(struct kvm_vm *vm)
{
- TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
- "unknown or unsupported guest mode, mode: 0x%x", vm->mode);
+ TEST_ASSERT((vm->mode == VM_MODE_PXXV48_4K) || (vm->mode == VM_MODE_PXXV48_4K_USER),
+ "Attempt to use unknown or unsupported guest mode, mode: 0x%x", vm->mode);

/* If needed, create page map l4 table. */
if (!vm->pgd_created) {
@@ -159,6 +159,8 @@ static uint64_t *virt_create_upper_pte(struct kvm_vm *vm,

if (!(*pte & PTE_PRESENT_MASK)) {
*pte = PTE_PRESENT_MASK | PTE_WRITABLE_MASK;
+ if (vm->mode == VM_MODE_PXXV48_4K_USER)
+ *pte |= PTE_USER_MASK;
if (current_level == target_level)
*pte |= PTE_LARGE_MASK | (paddr & PHYSICAL_PAGE_MASK);
else
@@ -185,7 +187,7 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
uint64_t *pml4e, *pdpe, *pde;
uint64_t *pte;

- TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K,
+ TEST_ASSERT((vm->mode == VM_MODE_PXXV48_4K) || (vm->mode == VM_MODE_PXXV48_4K_USER),
"Unknown or unsupported guest mode, mode: 0x%x", vm->mode);

TEST_ASSERT((vaddr % pg_size) == 0,
@@ -222,6 +224,8 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
TEST_ASSERT(!(*pte & PTE_PRESENT_MASK),
"PTE already present for 4k page at vaddr: 0x%lx\n", vaddr);
*pte = PTE_PRESENT_MASK | PTE_WRITABLE_MASK | (paddr & PHYSICAL_PAGE_MASK);
+ if (vm->mode == VM_MODE_PXXV48_4K_USER)
+ *pte |= PTE_USER_MASK;
}

void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
@@ -268,8 +272,8 @@ uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
TEST_ASSERT(*level >= PG_LEVEL_NONE && *level < PG_LEVEL_NUM,
"Invalid PG_LEVEL_* '%d'", *level);

- TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
- "unknown or unsupported guest mode, mode: 0x%x", vm->mode);
+ TEST_ASSERT((vm->mode == VM_MODE_PXXV48_4K) || (vm->mode == VM_MODE_PXXV48_4K_USER),
+ "Attempt to use unknown or unsupported guest mode, mode: 0x%x", vm->mode);
TEST_ASSERT(sparsebit_is_set(vm->vpages_valid,
(vaddr >> vm->page_shift)),
"Invalid virtual address, vaddr: 0x%lx",
@@ -536,6 +540,7 @@ static void vcpu_setup(struct kvm_vm *vm, struct kvm_vcpu *vcpu)

switch (vm->mode) {
case VM_MODE_PXXV48_4K:
+ case VM_MODE_PXXV48_4K_USER:
sregs.cr0 = X86_CR0_PE | X86_CR0_NE | X86_CR0_PG;
sregs.cr4 |= X86_CR4_PAE | X86_CR4_OSFXSR;
sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX);
diff --git a/tools/testing/selftests/kvm/lib/x86_64/vmx.c b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
index 59d97531c9b1..65147de6f9c0 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/vmx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
@@ -403,8 +403,8 @@ void __nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
struct eptPageTableEntry *pt = vmx->eptp_hva, *pte;
uint16_t index;

- TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
- "unknown or unsupported guest mode, mode: 0x%x", vm->mode);
+ TEST_ASSERT((vm->mode == VM_MODE_PXXV48_4K) || (vm->mode == VM_MODE_PXXV48_4K_USER),
+ "Attempt to use unknown or unsupported guest mode, mode: 0x%x", vm->mode);

TEST_ASSERT((nested_paddr >> 48) == 0,
"Nested physical address 0x%lx requires 5-level paging",
--
2.42.0