Hi, Bibo,
On Wed, Apr 16, 2025 at 11:55 AM Bibo Mao <maob...@loongson.cn> wrote:
>
> Add core KVM selftests support for LoongArch, it includes exception
> handler, mmu page table setup and vCPU startup entry support.
>
> Signed-off-by: Bibo Mao <maob...@loongson.cn>
> ---
> .../selftests/kvm/lib/loongarch/exception.S | 59 +++
> .../selftests/kvm/lib/loongarch/processor.c | 347 ++++++++++++++++++
> 2 files changed, 406 insertions(+)
> create mode 100644 tools/testing/selftests/kvm/lib/loongarch/exception.S
> create mode 100644 tools/testing/selftests/kvm/lib/loongarch/processor.c
>
> diff --git a/tools/testing/selftests/kvm/lib/loongarch/exception.S
> b/tools/testing/selftests/kvm/lib/loongarch/exception.S
> new file mode 100644
> index 000000000000..88bfa505c6f5
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/loongarch/exception.S
> @@ -0,0 +1,59 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#include "processor.h"
> +
> +/* address of refill exception should be 4K aligned */
> +.balign 4096
> +.global handle_tlb_refill
> +handle_tlb_refill:
> + csrwr t0, LOONGARCH_CSR_TLBRSAVE
> + csrrd t0, LOONGARCH_CSR_PGD
> + lddir t0, t0, 3
> + lddir t0, t0, 1
> + ldpte t0, 0
> + ldpte t0, 1
> + tlbfill
> + csrrd t0, LOONGARCH_CSR_TLBRSAVE
> + ertn
> +
> + /*
> + * save and restore all gprs except base register,
> + * and default value of base register is sp ($r3).
> + */
> +.macro save_gprs base
> + .irp
> n,1,2,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
> + st.d $r\n, \base, 8 * \n
> + .endr
> +.endm
> +
> +.macro restore_gprs base
> + .irp
> n,1,2,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
> + ld.d $r\n, \base, 8 * \n
> + .endr
> +.endm
> +
> +/* address of general exception should be 4K aligned */
> +.balign 4096
> +.global handle_exception
> +handle_exception:
> + csrwr sp, LOONGARCH_CSR_KS0
> + csrrd sp, LOONGARCH_CSR_KS1
> + addi.d sp, sp, -EXREGS_SIZE
> +
> + save_gprs sp
> + /* save sp register to stack */
> + csrrd t0, LOONGARCH_CSR_KS0
> + st.d t0, sp, 3 * 8
> +
> + csrrd t0, LOONGARCH_CSR_ERA
> + st.d t0, sp, PC_OFFSET_EXREGS
> + csrrd t0, LOONGARCH_CSR_ESTAT
> + st.d t0, sp, ESTAT_OFFSET_EXREGS
> + csrrd t0, LOONGARCH_CSR_BADV
> + st.d t0, sp, BADV_OFFSET_EXREGS
> +
> + or a0, sp, zero
> + bl route_exception
> + restore_gprs sp
> + csrrd sp, LOONGARCH_CSR_KS0
> + ertn
> diff --git a/tools/testing/selftests/kvm/lib/loongarch/processor.c
> b/tools/testing/selftests/kvm/lib/loongarch/processor.c
> new file mode 100644
> index 000000000000..8595c38ca26b
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/loongarch/processor.c
> @@ -0,0 +1,347 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <assert.h>
> +#include <linux/compiler.h>
> +
> +#include "kvm_util.h"
> +#include "processor.h"
> +#include "ucall_common.h"
> +
> +#define LOONGARCH_GUEST_STACK_VADDR_MIN 0x200000
> +#define LOONARCH_PAGE_TABLE_PHYS_MIN 0x200000
I think here is a typo.
Huacai
> +
> +static vm_paddr_t invalid_pgtable[4];
> +static uint64_t virt_pte_index(struct kvm_vm *vm, vm_vaddr_t gva, int level)
> +{
> + unsigned int shift;
> + uint64_t mask;
> +
> + shift = level * (vm->page_shift - 3) + vm->page_shift;
> + mask = (1UL << (vm->page_shift - 3)) - 1;
> + return (gva >> shift) & mask;
> +}
> +
> +static uint64_t pte_addr(struct kvm_vm *vm, uint64_t entry)
> +{
> + return entry & ~((0x1UL << vm->page_shift) - 1);
> +}
> +
> +static uint64_t ptrs_per_pte(struct kvm_vm *vm)
> +{
> + return 1 << (vm->page_shift - 3);
> +}
> +
> +static void virt_set_pgtable(struct kvm_vm *vm, vm_paddr_t table, vm_paddr_t
> child)
> +{
> + uint64_t *ptep;
> + int i, ptrs_per_pte;
> +
> + ptep = addr_gpa2hva(vm, table);
> + ptrs_per_pte = 1 << (vm->page_shift - 3);
> + for (i = 0; i < ptrs_per_pte; i++)
> + WRITE_ONCE(*(ptep + i), child);
> +}
> +
> +void virt_arch_pgd_alloc(struct kvm_vm *vm)
> +{
> + int i;
> + vm_paddr_t child, table;
> +
> + if (vm->pgd_created)
> + return;
> + child = table = 0;
> + for (i = 0; i < vm->pgtable_levels; i++) {
> + invalid_pgtable[i] = child;
> + table = vm_phy_page_alloc(vm, LOONARCH_PAGE_TABLE_PHYS_MIN,
> + vm->memslots[MEM_REGION_PT]);
> + TEST_ASSERT(table, "Fail to allocate page tale at level
> %d\n", i);
> + virt_set_pgtable(vm, table, child);
> + child = table;
> + }
> + vm->pgd = table;
> + vm->pgd_created = true;
> +}
> +
> +static int virt_pte_none(uint64_t *ptep, int level)
> +{
> + return *ptep == invalid_pgtable[level];
> +}
> +
> +static uint64_t *virt_populate_pte(struct kvm_vm *vm, vm_vaddr_t gva, int
> alloc)
> +{
> + uint64_t *ptep;
> + vm_paddr_t child;
> + int level;
> +
> + if (!vm->pgd_created)
> + goto unmapped_gva;
> +
> + level = vm->pgtable_levels - 1;
> + child = vm->pgd;
> + while (level > 0) {
> + ptep = addr_gpa2hva(vm, child) + virt_pte_index(vm, gva,
> level) * 8;
> + if (virt_pte_none(ptep, level)) {
> + if (alloc) {
> + child = vm_alloc_page_table(vm);
> + virt_set_pgtable(vm, child,
> invalid_pgtable[level - 1]);
> + WRITE_ONCE(*ptep, child);
> + } else
> + goto unmapped_gva;
> +
> + } else
> + child = pte_addr(vm, *ptep);
> + level--;
> + }
> +
> + ptep = addr_gpa2hva(vm, child) + virt_pte_index(vm, gva, level) * 8;
> + return ptep;
> +
> +unmapped_gva:
> + TEST_FAIL("No mapping for vm virtual address, gva: 0x%lx", gva);
> + exit(EXIT_FAILURE);
> +}
> +
> +vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
> +{
> + uint64_t *ptep;
> +
> + ptep = virt_populate_pte(vm, gva, 0);
> + TEST_ASSERT(*ptep != 0, "Virtual address vaddr: 0x%lx not mapped\n",
> gva);
> +
> + return pte_addr(vm, *ptep) + (gva & (vm->page_size - 1));
> +}
> +
> +void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
> +{
> + uint32_t prot_bits;
> + uint64_t *ptep;
> +
> + TEST_ASSERT((vaddr % vm->page_size) == 0,
> + "Virtual address not on page boundary,\n"
> + "vaddr: 0x%lx vm->page_size: 0x%x", vaddr,
> vm->page_size);
> + TEST_ASSERT(sparsebit_is_set(vm->vpages_valid,
> + (vaddr >> vm->page_shift)),
> + "Invalid virtual address, vaddr: 0x%lx", vaddr);
> + TEST_ASSERT((paddr % vm->page_size) == 0,
> + "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 = virt_populate_pte(vm, vaddr, 1);
> + prot_bits = _PAGE_PRESENT | __READABLE | __WRITEABLE | _CACHE_CC;
> + prot_bits |= _PAGE_USER;
> + WRITE_ONCE(*ptep, paddr | prot_bits);
> +}
> +
> +static void pte_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent,
> uint64_t page, int level)
> +{
> + static const char * const type[] = { "pte", "pmd", "pud", "pgd"};
> + uint64_t pte, *ptep;
> +
> + if (level < 0)
> + return;
> +
> + for (pte = page; pte < page + ptrs_per_pte(vm) * 8; pte += 8) {
> + ptep = addr_gpa2hva(vm, pte);
> + if (virt_pte_none(ptep, level))
> + continue;
> + fprintf(stream, "%*s%s: %lx: %lx at %p\n",
> + indent, "", type[level], pte, *ptep, ptep);
> + pte_dump(stream, vm, indent + 1, pte_addr(vm, *ptep),
> level--);
> + }
> +}
> +
> +void virt_arch_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)
> +{
> + int level;
> +
> + if (!vm->pgd_created)
> + return;
> +
> + level = vm->pgtable_levels - 1;
> + pte_dump(stream, vm, indent, vm->pgd, level);
> +}
> +
> +void vcpu_arch_dump(FILE *stream, struct kvm_vcpu *vcpu, uint8_t indent)
> +{
> +}
> +
> +void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
> +{
> + struct ucall uc;
> +
> + if (get_ucall(vcpu, &uc) != UCALL_UNHANDLED)
> + return;
> +
> + TEST_FAIL("Unexpected exception (pc:0x%lx, estat:0x%lx, badv:0x%lx)",
> + uc.args[0], uc.args[1], uc.args[2]);
> +}
> +
> +void route_exception(struct ex_regs *regs)
> +{
> + unsigned long pc, estat, badv;
> +
> + pc = regs->pc;
> + estat = regs->estat;
> + badv = regs->badv;
> + ucall(UCALL_UNHANDLED, 3, pc, estat, badv);
> + while (1)
> + ;
> +}
> +
> +void vcpu_args_set(struct kvm_vcpu *vcpu, unsigned int num, ...)
> +{
> + va_list ap;
> + struct kvm_regs regs;
> + int i;
> +
> + TEST_ASSERT(num >= 1 && num <= 8, "Unsupported number of args,\n"
> + "num: %u\n", num);
> +
> + vcpu_regs_get(vcpu, ®s);
> + va_start(ap, num);
> + for (i = 0; i < num; i++)
> + regs.gpr[i + 4] = va_arg(ap, uint64_t);
> + va_end(ap);
> + vcpu_regs_set(vcpu, ®s);
> +}
> +
> +static void loongarch_get_csr(struct kvm_vcpu *vcpu, uint64_t id, void *addr)
> +{
> + uint64_t csrid;
> +
> + csrid = KVM_REG_LOONGARCH_CSR | KVM_REG_SIZE_U64 | 8 * id;
> + __vcpu_get_reg(vcpu, csrid, addr);
> +}
> +
> +static void loongarch_set_csr(struct kvm_vcpu *vcpu, uint64_t id, uint64_t
> val)
> +{
> + uint64_t csrid;
> +
> + csrid = KVM_REG_LOONGARCH_CSR | KVM_REG_SIZE_U64 | 8 * id;
> + vcpu_set_reg(vcpu, csrid, val);
> +}
> +
> +static void loongarch_vcpu_setup(struct kvm_vcpu *vcpu)
> +{
> + unsigned long val;
> + int width;
> + struct kvm_vm *vm = vcpu->vm;
> +
> + switch (vm->mode) {
> + case VM_MODE_P36V47_16K:
> + case VM_MODE_P47V47_16K:
> + break;
> +
> + default:
> + TEST_FAIL("Unknown guest mode, mode: 0x%x", vm->mode);
> + }
> +
> + /* user mode and page enable mode */
> + val = PLV_USER | CSR_CRMD_PG;
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_CRMD, val);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_PRMD, val);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_EUEN, 1);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_ECFG, 0);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_TCFG, 0);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_ASID, 1);
> +
> + width = vm->page_shift - 3;
> + val = 0;
> + switch (vm->pgtable_levels) {
> + case 4:
> + /* pud page shift and width */
> + val = (vm->page_shift + width * 2) << 20 | (width << 25);
> + /* fall throuth */
> + case 3:
> + /* pmd page shift and width */
> + val |= (vm->page_shift + width) << 10 | (width << 15);
> + /* pte page shift and width */
> + val |= vm->page_shift | width << 5;
> + break;
> + default:
> + TEST_FAIL("Got %u page table levels, expected 3 or 4",
> vm->pgtable_levels);
> + }
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_PWCTL0, val);
> +
> + /* PGD page shift and width */
> + val = (vm->page_shift + width * (vm->pgtable_levels - 1)) | width <<
> 6;
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_PWCTL1, val);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_PGDL, vm->pgd);
> +
> + /*
> + * Refill exception runs on real mode
> + * Entry address should be physical address
> + */
> + val = addr_gva2gpa(vm, (unsigned long)handle_tlb_refill);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_TLBRENTRY, val);
> +
> + /*
> + * General exception runs on page-enabled mode
> + * Entry address should be virtual address
> + */
> + val = (unsigned long)handle_exception;
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_EENTRY, val);
> +
> + loongarch_get_csr(vcpu, LOONGARCH_CSR_TLBIDX, &val);
> + val &= ~CSR_TLBIDX_SIZEM;
> + val |= PS_DEFAULT_SIZE << CSR_TLBIDX_SIZE;
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_TLBIDX, val);
> +
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_STLBPGSIZE, PS_DEFAULT_SIZE);
> +
> + /* LOONGARCH_CSR_KS1 is used for exception stack */
> + val = __vm_vaddr_alloc(vm, vm->page_size,
> + LOONGARCH_GUEST_STACK_VADDR_MIN, MEM_REGION_DATA);
> + TEST_ASSERT(val != 0, "No memory for exception stack");
> + val = val + vm->page_size;
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_KS1, val);
> +
> + loongarch_get_csr(vcpu, LOONGARCH_CSR_TLBREHI, &val);
> + val &= ~CSR_TLBREHI_PS;
> + val |= PS_DEFAULT_SIZE << CSR_TLBREHI_PS_SHIFT;
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_TLBREHI, val);
> +
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_CPUID, vcpu->id);
> + loongarch_set_csr(vcpu, LOONGARCH_CSR_TMID, vcpu->id);
> +}
> +
> +static struct kvm_vcpu *loongarch_vcpu_add(struct kvm_vm *vm, uint32_t
> vcpu_id)
> +{
> + size_t stack_size;
> + uint64_t stack_vaddr;
> + struct kvm_regs regs;
> + struct kvm_vcpu *vcpu;
> +
> + vcpu = __vm_vcpu_add(vm, vcpu_id);
> + stack_size = vm->page_size;
> + stack_vaddr = __vm_vaddr_alloc(vm, stack_size,
> + LOONGARCH_GUEST_STACK_VADDR_MIN, MEM_REGION_DATA);
> + TEST_ASSERT(stack_vaddr != 0, "No memory for vm stack");
> +
> + loongarch_vcpu_setup(vcpu);
> + /* Setup guest general purpose registers */
> + vcpu_regs_get(vcpu, ®s);
> + regs.gpr[3] = stack_vaddr + stack_size;
> + vcpu_regs_set(vcpu, ®s);
> +
> + return vcpu;
> +}
> +
> +struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id)
> +{
> + return loongarch_vcpu_add(vm, vcpu_id);
> +}
> +
> +void vcpu_arch_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code)
> +{
> + struct kvm_regs regs;
> +
> + /* Setup guest PC register */
> + vcpu_regs_get(vcpu, ®s);
> + regs.pc = (uint64_t)guest_code;
> + vcpu_regs_set(vcpu, ®s);
> +}
> --
> 2.39.3
>
