Commit a457fd56 authored by Anup Patel's avatar Anup Patel Committed by Anup Patel
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RISC-V: KVM: Add VM capability to allow userspace get GPA bits 



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: default avatarAnup Patel <anup.patel@wdc.com>
Reviewed-and-tested-by: default avatarAtish Patra <atishp@rivosinc.com>
parent ef8949a9

arch/riscv/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -218,6 +218,7 @@ 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);

arch/riscv/kvm/mmu.c

+5 −0
Original line number Diff line number Diff line
@@ -769,3 +769,8 @@ unsigned long kvm_riscv_stage2_mode(void) 
{

	return stage2_mode >> HGATP_MODE_SHIFT;

}



int kvm_riscv_stage2_gpa_bits(void)

{

	return stage2_gpa_bits;

}

arch/riscv/kvm/vm.c

+3 −0
Original line number Diff line number Diff line
@@ -74,6 +74,9 @@ 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;

include/uapi/linux/kvm.h

+1 −0
Original line number Diff line number Diff line
@@ -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