Introduce library functions for setting up guest stage-2 page tables, then use that to give L2 an identity mapped stage-2 and enable it.
The translation and stage-2 page table built is simple, start level 0, 4 levels, 4KB granules, normal cachable, 48-bit IA, 40-bit OA. The nested page table code is adapted from lib/x86/vmx.c. Signed-off-by: Wei-Lin Chang <[email protected]> --- .../selftests/kvm/include/arm64/nested.h | 7 ++ .../selftests/kvm/include/arm64/processor.h | 9 ++ .../testing/selftests/kvm/lib/arm64/nested.c | 97 ++++++++++++++++++- 3 files changed, 111 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/include/arm64/nested.h b/tools/testing/selftests/kvm/include/arm64/nested.h index 739ff2ee0161..0be10a775e48 100644 --- a/tools/testing/selftests/kvm/include/arm64/nested.h +++ b/tools/testing/selftests/kvm/include/arm64/nested.h @@ -6,6 +6,13 @@ #ifndef SELFTEST_KVM_NESTED_H #define SELFTEST_KVM_NESTED_H +uint64_t get_l1_vtcr(void); + +void nested_map(struct kvm_vm *vm, vm_paddr_t guest_pgd, + uint64_t nested_paddr, uint64_t paddr, uint64_t size); +void nested_map_memslot(struct kvm_vm *vm, vm_paddr_t guest_pgd, + uint32_t memslot); + void prepare_l2_stack(struct kvm_vm *vm, struct kvm_vcpu *vcpu); void prepare_hyp_state(struct kvm_vm *vm, struct kvm_vcpu *vcpu); void prepare_eret_destination(struct kvm_vm *vm, struct kvm_vcpu *vcpu, void *l2_pc); diff --git a/tools/testing/selftests/kvm/include/arm64/processor.h b/tools/testing/selftests/kvm/include/arm64/processor.h index ac97a1c436fc..5de2e932d95a 100644 --- a/tools/testing/selftests/kvm/include/arm64/processor.h +++ b/tools/testing/selftests/kvm/include/arm64/processor.h @@ -104,6 +104,15 @@ #define TCR_HA (UL(1) << 39) #define TCR_DS (UL(1) << 59) +/* VTCR_EL2 specific flags */ +#define VTCR_EL2_T0SZ_BITS(x) ((UL(64) - (x)) << VTCR_EL2_T0SZ_SHIFT) + +#define VTCR_EL2_SL0_LV0_4K (UL(2) << VTCR_EL2_SL0_SHIFT) +#define VTCR_EL2_SL0_LV1_4K (UL(1) << VTCR_EL2_SL0_SHIFT) +#define VTCR_EL2_SL0_LV2_4K (UL(0) << VTCR_EL2_SL0_SHIFT) + +#define VTCR_EL2_PS_40_BITS (UL(2) << VTCR_EL2_PS_SHIFT) + /* * AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers). */ diff --git a/tools/testing/selftests/kvm/lib/arm64/nested.c b/tools/testing/selftests/kvm/lib/arm64/nested.c index 111d02f44cfe..910f8cd30f96 100644 --- a/tools/testing/selftests/kvm/lib/arm64/nested.c +++ b/tools/testing/selftests/kvm/lib/arm64/nested.c @@ -1,8 +1,11 @@ // SPDX-License-Identifier: GPL-2.0 /* - * ARM64 Nested virtualization helpers + * ARM64 Nested virtualization helpers, nested page table code adapted from + * ../x86/vmx.c. */ +#include <linux/sizes.h> + #include "kvm_util.h" #include "nested.h" #include "processor.h" @@ -18,6 +21,87 @@ static void hvc_handler(struct ex_regs *regs) regs->pc = (u64)after_hvc; } +uint64_t get_l1_vtcr(void) +{ + return VTCR_EL2_PS_40_BITS | VTCR_EL2_TG0_4K | VTCR_EL2_ORGN0_WBWA | + VTCR_EL2_IRGN0_WBWA | VTCR_EL2_SL0_LV0_4K | VTCR_EL2_T0SZ_BITS(48); +} + +static void __nested_pg_map(struct kvm_vm *vm, uint64_t guest_pgd, + uint64_t nested_paddr, uint64_t paddr, uint64_t flags) +{ + uint8_t attr_idx = flags & (PTE_ATTRINDX_MASK >> PTE_ATTRINDX_SHIFT); + uint64_t pg_attr; + uint64_t *ptep; + + TEST_ASSERT((nested_paddr % vm->page_size) == 0, + "L2 IPA not on page boundary,\n" + " nested_paddr: 0x%lx vm->page_size: 0x%x", nested_paddr, vm->page_size); + TEST_ASSERT((paddr % vm->page_size) == 0, + "Guest physical address not on page boundary,\n" + " paddr: 0x%lx vm->page_size: 0x%x", paddr, vm->page_size); + TEST_ASSERT((paddr >> vm->page_shift) <= vm->max_gfn, + "Physical address beyond maximum supported,\n" + " paddr: 0x%lx vm->max_gfn: 0x%lx vm->page_size: 0x%x", + paddr, vm->max_gfn, vm->page_size); + + ptep = addr_gpa2hva(vm, guest_pgd) + ((nested_paddr >> 39) & 0x1ffu) * 8; + if (!*ptep) + *ptep = (vm_alloc_page_table(vm) & GENMASK(47, 12)) | PGD_TYPE_TABLE | PTE_VALID; + ptep = addr_gpa2hva(vm, *ptep & GENMASK(47, 12)) + ((nested_paddr >> 30) & 0x1ffu) * 8; + if (!*ptep) + *ptep = (vm_alloc_page_table(vm) & GENMASK(47, 12)) | PUD_TYPE_TABLE | PTE_VALID; + ptep = addr_gpa2hva(vm, *ptep & GENMASK(47, 12)) + ((nested_paddr >> 21) & 0x1ffu) * 8; + if (!*ptep) + *ptep = (vm_alloc_page_table(vm) & GENMASK(47, 12)) | PMD_TYPE_TABLE | PTE_VALID; + ptep = addr_gpa2hva(vm, *ptep & GENMASK(47, 12)) + ((nested_paddr >> 12) & 0x1ffu) * 8; + + pg_attr = PTE_AF | PTE_ATTRINDX(attr_idx) | PTE_TYPE_PAGE | PTE_VALID; + pg_attr |= PTE_SHARED; + + *ptep = (paddr & GENMASK(47, 12)) | pg_attr; +} + +void nested_map(struct kvm_vm *vm, vm_paddr_t guest_pgd, + uint64_t nested_paddr, uint64_t paddr, uint64_t size) +{ + size_t npages = size / SZ_4K; + + TEST_ASSERT(nested_paddr + size > nested_paddr, "Vaddr overflow"); + TEST_ASSERT(paddr + size > paddr, "Paddr overflow"); + + while (npages--) { + __nested_pg_map(vm, guest_pgd, nested_paddr, paddr, MT_NORMAL); + nested_paddr += SZ_4K; + paddr += SZ_4K; + } +} + +/* + * Prepare an identity shadow page table that maps all the + * physical pages in VM. + */ +void nested_map_memslot(struct kvm_vm *vm, vm_paddr_t guest_pgd, + uint32_t memslot) +{ + sparsebit_idx_t i, last; + struct userspace_mem_region *region = + memslot2region(vm, memslot); + + i = (region->region.guest_phys_addr >> vm->page_shift) - 1; + last = i + (region->region.memory_size >> vm->page_shift); + for (;;) { + i = sparsebit_next_clear(region->unused_phy_pages, i); + if (i > last) + break; + + nested_map(vm, guest_pgd, + (uint64_t)i << vm->page_shift, + (uint64_t)i << vm->page_shift, + 1 << vm->page_shift); + } +} + void prepare_l2_stack(struct kvm_vm *vm, struct kvm_vcpu *vcpu) { size_t l2_stack_size; @@ -32,7 +116,16 @@ void prepare_l2_stack(struct kvm_vm *vm, struct kvm_vcpu *vcpu) void prepare_hyp_state(struct kvm_vm *vm, struct kvm_vcpu *vcpu) { - vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_HCR_EL2), HCR_EL2_RW); + vm_paddr_t guest_pgd; + + guest_pgd = vm_phy_pages_alloc(vm, 1, + KVM_GUEST_PAGE_TABLE_MIN_PADDR, + vm->memslots[MEM_REGION_PT]); + nested_map_memslot(vm, guest_pgd, 0); + + vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_HCR_EL2), HCR_EL2_RW | HCR_EL2_VM); + vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_VTTBR_EL2), guest_pgd); + vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_VTCR_EL2), get_l1_vtcr()); } void prepare_eret_destination(struct kvm_vm *vm, struct kvm_vcpu *vcpu, void *l2_pc) -- 2.43.0
