The number of GPA bits supported for a RISC-V Guest/VM is based on the MMU mode used by the G-stage translation. The KVM RISC-V will detect and use the best possible MMU mode for the G-stage in kvm_arch_init().
We add a generic VM capability KVM_CAP_VM_GPA_BITS which can be used by the KVM userspace to get the number of GPA (guest physical address) bits supported for a Guest/VM.
Signed-off-by: Anup Patel anup.patel@wdc.com Reviewed-and-tested-by: Atish Patra atishp@rivosinc.com --- arch/riscv/include/asm/kvm_host.h | 1 + arch/riscv/kvm/mmu.c | 5 +++++ arch/riscv/kvm/vm.c | 3 +++ include/uapi/linux/kvm.h | 1 + 4 files changed, 10 insertions(+)
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 247b761c72fd..ac38696abedf 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -219,6 +219,7 @@ void kvm_riscv_stage2_free_pgd(struct kvm *kvm); void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu); void kvm_riscv_stage2_mode_detect(void); unsigned long kvm_riscv_stage2_mode(void); +int kvm_riscv_stage2_gpa_bits(void);
void kvm_riscv_stage2_vmid_detect(void); unsigned long kvm_riscv_stage2_vmid_bits(void); diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index d0efdc2259dc..58a47c93e5f9 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -766,3 +766,8 @@ unsigned long kvm_riscv_stage2_mode(void) { return stage2_mode >> HGATP_MODE_SHIFT; } + +int kvm_riscv_stage2_gpa_bits(void) +{ + return stage2_gpa_bits; +} diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c index fb18af34a4b5..1e12c19a7c6a 100644 --- a/arch/riscv/kvm/vm.c +++ b/arch/riscv/kvm/vm.c @@ -82,6 +82,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_NR_MEMSLOTS: r = KVM_USER_MEM_SLOTS; break; + case KVM_CAP_VM_GPA_BITS: + r = kvm_riscv_stage2_gpa_bits(); + break; default: r = 0; break; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 1daa45268de2..469f05d69c8d 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1131,6 +1131,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204 #define KVM_CAP_ARM_MTE 205 #define KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 206 +#define KVM_CAP_VM_GPA_BITS 207
#ifdef KVM_CAP_IRQ_ROUTING