[PATCH v2] KVM: riscv: selftests: Add riscv vm satp modes

* [PATCH v2] KVM: riscv: selftests: Add riscv vm satp modes 
@ 2025-10-29 11:20 wu.fei9
  2025-10-31 19:26 ` Andrew Jones
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: wu.fei9 @ 2025-10-29 11:20 UTC (permalink / raw)
  To: kvm-riscv, ajones, rkrcmar

Current vm modes cannot represent riscv guest modes precisely, here add
all 9 combinations of P(56,40,41) x V(57,48,39). Also the default vm
mode is detected on runtime instead of hardcoded one, which might not be
supported on specific machine.

Signed-off-by: Wu Fei <wu.fei9@sanechips.com.cn>
---
 .../testing/selftests/kvm/include/kvm_util.h  | 17 ++++-
 .../selftests/kvm/include/riscv/processor.h   |  2 +
 tools/testing/selftests/kvm/lib/guest_modes.c | 41 +++++++++---
 tools/testing/selftests/kvm/lib/kvm_util.c    | 33 ++++++++++
 .../selftests/kvm/lib/riscv/processor.c       | 63 +++++++++++++++++--
 5 files changed, 142 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index bee65ca08721..2055f0f5df82 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -179,6 +179,17 @@ enum vm_guest_mode {
        VM_MODE_P36V48_64K,
        VM_MODE_P47V47_16K,
        VM_MODE_P36V47_16K,
+
+       VM_MODE_P56V57_4K,      /* For riscv64 */
+       VM_MODE_P56V48_4K,
+       VM_MODE_P56V39_4K,
+       VM_MODE_P50V57_4K,
+       VM_MODE_P50V48_4K,
+       VM_MODE_P50V39_4K,
+       VM_MODE_P41V57_4K,
+       VM_MODE_P41V48_4K,
+       VM_MODE_P41V39_4K,
+
        NUM_VM_MODES,
 };

@@ -203,10 +214,10 @@ kvm_static_assert(sizeof(struct vm_shape) == sizeof(uint64_t));
        shape;                                  \
 })

-#if defined(__aarch64__)
-
 extern enum vm_guest_mode vm_mode_default;

+#if defined(__aarch64__)
+
 #define VM_MODE_DEFAULT                        vm_mode_default
 #define MIN_PAGE_SHIFT                 12U
 #define ptes_per_page(page_size)       ((page_size) / 8)
@@ -229,7 +240,7 @@ extern enum vm_guest_mode vm_mode_default;
 #error "RISC-V 32-bit kvm selftests not supported"
 #endif

-#define VM_MODE_DEFAULT                        VM_MODE_P40V48_4K
+#define VM_MODE_DEFAULT                        vm_mode_default
 #define MIN_PAGE_SHIFT                 12U
 #define ptes_per_page(page_size)       ((page_size) / 8)

diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h b/tools/testing/selftests/kvm/include/riscv/processor.h
index 162f303d9daa..2d5a5548e698 100644
--- a/tools/testing/selftests/kvm/include/riscv/processor.h
+++ b/tools/testing/selftests/kvm/include/riscv/processor.h
@@ -191,4 +191,6 @@ static inline void local_irq_disable(void)
        csr_clear(CSR_SSTATUS, SR_SIE);
 }

+unsigned long riscv64_get_satp_mode(void);
+
 #endif /* SELFTEST_KVM_PROCESSOR_H */
diff --git a/tools/testing/selftests/kvm/lib/guest_modes.c b/tools/testing/selftests/kvm/lib/guest_modes.c
index b04901e55138..ce3099630397 100644
--- a/tools/testing/selftests/kvm/lib/guest_modes.c
+++ b/tools/testing/selftests/kvm/lib/guest_modes.c
@@ -4,7 +4,7 @@
  */
 #include "guest_modes.h"

-#ifdef __aarch64__
+#if defined(__aarch64__) || defined(__riscv)
 #include "processor.h"
 enum vm_guest_mode vm_mode_default;
 #endif
@@ -13,9 +13,11 @@ struct guest_mode guest_modes[NUM_VM_MODES];

 void guest_modes_append_default(void)
 {
-#ifndef __aarch64__
+#if !defined(__aarch64__) && !defined(__riscv)
        guest_mode_append(VM_MODE_DEFAULT, true);
-#else
+#endif
+
+#ifdef __aarch64__
        {
                unsigned int limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
                uint32_t ipa4k, ipa16k, ipa64k;
@@ -74,11 +76,36 @@ void guest_modes_append_default(void)
 #ifdef __riscv
        {
                unsigned int sz = kvm_check_cap(KVM_CAP_VM_GPA_BITS);
+               unsigned long satp_mode = riscv64_get_satp_mode() << SATP_MODE_SHIFT;
+               int i;

-               if (sz >= 52)
-                       guest_mode_append(VM_MODE_P52V48_4K, true);
-               if (sz >= 48)
-                       guest_mode_append(VM_MODE_P48V48_4K, true);
+               switch (sz) {
+               case 59:
+                       guest_mode_append(VM_MODE_P56V57_4K, satp_mode >= SATP_MODE_57);
+                       guest_mode_append(VM_MODE_P56V48_4K, satp_mode >= SATP_MODE_48);
+                       guest_mode_append(VM_MODE_P56V39_4K, satp_mode >= SATP_MODE_39);
+                       break;
+               case 50:
+                       guest_mode_append(VM_MODE_P50V57_4K, satp_mode >= SATP_MODE_57);
+                       guest_mode_append(VM_MODE_P50V48_4K, satp_mode >= SATP_MODE_48);
+                       guest_mode_append(VM_MODE_P50V39_4K, satp_mode >= SATP_MODE_39);
+                       break;
+               case 41:
+                       guest_mode_append(VM_MODE_P41V57_4K, satp_mode >= SATP_MODE_57);
+                       guest_mode_append(VM_MODE_P41V48_4K, satp_mode >= SATP_MODE_48);
+                       guest_mode_append(VM_MODE_P41V39_4K, satp_mode >= SATP_MODE_39);
+                       break;
+               default:
+                       break;
+               }
+
+               /* set the first supported mode as default */
+               vm_mode_default = NUM_VM_MODES;
+               for (i = 0; vm_mode_default == NUM_VM_MODES && i < NUM_VM_MODES; i++) {
+                       if (guest_modes[i].supported && guest_modes[i].enabled)
+                               vm_mode_default = i;
+               }
+               TEST_ASSERT(vm_mode_default != NUM_VM_MODES, "No supported mode!");
        }
 #endif
 }
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index a055343a7bf7..9803e61ae7db 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -224,6 +224,15 @@ const char *vm_guest_mode_string(uint32_t i)
                [VM_MODE_P36V48_64K]    = "PA-bits:36,  VA-bits:48, 64K pages",
                [VM_MODE_P47V47_16K]    = "PA-bits:47,  VA-bits:47, 16K pages",
                [VM_MODE_P36V47_16K]    = "PA-bits:36,  VA-bits:47, 16K pages",
+               [VM_MODE_P56V57_4K]     = "PA-bits:56,  VA-bits:57,  4K pages",
+               [VM_MODE_P56V48_4K]     = "PA-bits:56,  VA-bits:48,  4K pages",
+               [VM_MODE_P56V39_4K]     = "PA-bits:56,  VA-bits:39,  4K pages",
+               [VM_MODE_P50V57_4K]     = "PA-bits:50,  VA-bits:57,  4K pages",
+               [VM_MODE_P50V48_4K]     = "PA-bits:50,  VA-bits:48,  4K pages",
+               [VM_MODE_P50V39_4K]     = "PA-bits:50,  VA-bits:39,  4K pages",
+               [VM_MODE_P41V57_4K]     = "PA-bits:41,  VA-bits:57,  4K pages",
+               [VM_MODE_P41V48_4K]     = "PA-bits:41,  VA-bits:48,  4K pages",
+               [VM_MODE_P41V39_4K]     = "PA-bits:41,  VA-bits:39,  4K pages",
        };
        _Static_assert(sizeof(strings)/sizeof(char *) == NUM_VM_MODES,
                       "Missing new mode strings?");
@@ -251,6 +260,15 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
        [VM_MODE_P36V48_64K]    = { 36, 48, 0x10000, 16 },
        [VM_MODE_P47V47_16K]    = { 47, 47,  0x4000, 14 },
        [VM_MODE_P36V47_16K]    = { 36, 47,  0x4000, 14 },
+       [VM_MODE_P56V57_4K]     = { 56, 57,  0x1000, 12 },
+       [VM_MODE_P56V48_4K]     = { 56, 48,  0x1000, 12 },
+       [VM_MODE_P56V39_4K]     = { 56, 39,  0x1000, 12 },
+       [VM_MODE_P50V57_4K]     = { 50, 57,  0x1000, 12 },
+       [VM_MODE_P50V48_4K]     = { 50, 48,  0x1000, 12 },
+       [VM_MODE_P50V39_4K]     = { 50, 39,  0x1000, 12 },
+       [VM_MODE_P41V57_4K]     = { 41, 57,  0x1000, 12 },
+       [VM_MODE_P41V48_4K]     = { 41, 48,  0x1000, 12 },
+       [VM_MODE_P41V39_4K]     = { 41, 39,  0x1000, 12 },
 };
 _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
               "Missing new mode params?");
@@ -351,6 +369,21 @@ struct kvm_vm *____vm_create(struct vm_shape shape)
        case VM_MODE_P44V64_4K:
                vm->pgtable_levels = 5;
                break;
+       case VM_MODE_P56V57_4K:
+       case VM_MODE_P50V57_4K:
+       case VM_MODE_P41V57_4K:
+               vm->pgtable_levels = 5;
+               break;
+       case VM_MODE_P56V48_4K:
+       case VM_MODE_P50V48_4K:
+       case VM_MODE_P41V48_4K:
+               vm->pgtable_levels = 4;
+               break;
+       case VM_MODE_P56V39_4K:
+       case VM_MODE_P50V39_4K:
+       case VM_MODE_P41V39_4K:
+               vm->pgtable_levels = 3;
+               break;
        default:
                TEST_FAIL("Unknown guest mode: 0x%x", vm->mode);
        }
diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
index 2eac7d4b59e9..53675292b8eb 100644
--- a/tools/testing/selftests/kvm/lib/riscv/processor.c
+++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
@@ -8,6 +8,7 @@
 #include <linux/compiler.h>
 #include <assert.h>

+#include "guest_modes.h"
 #include "kvm_util.h"
 #include "processor.h"
 #include "ucall_common.h"
@@ -197,22 +198,41 @@ void riscv_vcpu_mmu_setup(struct kvm_vcpu *vcpu)
 {
        struct kvm_vm *vm = vcpu->vm;
        unsigned long satp;
+       unsigned long satp_mode;
+       unsigned long max_satp_mode;

        /*
         * The RISC-V Sv48 MMU mode supports 56-bit physical address
         * for 48-bit virtual address with 4KB last level page size.
         */
        switch (vm->mode) {
-       case VM_MODE_P52V48_4K:
-       case VM_MODE_P48V48_4K:
-       case VM_MODE_P40V48_4K:
+       case VM_MODE_P56V57_4K:
+       case VM_MODE_P50V57_4K:
+       case VM_MODE_P41V57_4K:
+               satp_mode = SATP_MODE_57;
+               break;
+       case VM_MODE_P56V48_4K:
+       case VM_MODE_P50V48_4K:
+       case VM_MODE_P41V48_4K:
+               satp_mode = SATP_MODE_48;
+               break;
+       case VM_MODE_P56V39_4K:
+       case VM_MODE_P50V39_4K:
+       case VM_MODE_P41V39_4K:
+               satp_mode = SATP_MODE_39;
                break;
        default:
                TEST_FAIL("Unknown guest mode, mode: 0x%x", vm->mode);
        }

+       max_satp_mode = vcpu_get_reg(vcpu, RISCV_CONFIG_REG(satp_mode));
+
+       if ((satp_mode >> SATP_MODE_SHIFT) > max_satp_mode)
+               TEST_FAIL("Unable to set satp mode 0x%lx, max mode 0x%lx\n",
+                         satp_mode >> SATP_MODE_SHIFT, max_satp_mode);
+
        satp = (vm->pgd >> PGTBL_PAGE_SIZE_SHIFT) & SATP_PPN;
-       satp |= SATP_MODE_48;
+       satp |= satp_mode;

        vcpu_set_reg(vcpu, RISCV_GENERAL_CSR_REG(satp), satp);
 }
@@ -515,3 +535,38 @@ unsigned long get_host_sbi_spec_version(void)

        return ret.value;
 }
+
+void kvm_selftest_arch_init(void)
+{
+       /*
+        * riscv64 doesn't have a true default mode, so start by detecting the
+        * supported vm mode.
+        */
+       guest_modes_append_default();
+}
+
+unsigned long riscv64_get_satp_mode(void)
+{
+       int kvm_fd, vm_fd, vcpu_fd, err;
+       uint64_t val;
+       struct kvm_one_reg reg = {
+               .id     = RISCV_CONFIG_REG(satp_mode),
+               .addr   = (uint64_t)&val,
+       };
+
+       kvm_fd = open_kvm_dev_path_or_exit();
+       vm_fd = __kvm_ioctl(kvm_fd, KVM_CREATE_VM, NULL);
+       TEST_ASSERT(vm_fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_VM, vm_fd));
+
+       vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0);
+       TEST_ASSERT(vcpu_fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_VCPU, vcpu_fd));
+
+       err = ioctl(vcpu_fd, KVM_GET_ONE_REG, &reg);
+       TEST_ASSERT(err == 0, KVM_IOCTL_ERROR(KVM_GET_ONE_REG, vcpu_fd));
+
+       close(vcpu_fd);
+       close(vm_fd);
+       close(kvm_fd);
+
+       return val;
+}
--
2.43.0

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