Messages in this thread | | | Date | Fri, 26 Nov 2021 17:13:36 +0100 | Subject | Re: [PATCH 2/4] RISC-V: KVM: Add VM capability to allow userspace get GPA size | From | Paolo Bonzini <> |
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On 11/26/21 16:40, Anup Patel wrote: > The GPA size supported for a RISC-V Guest/VM is based on the MMU mode > used by 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 RISC-V specific VM capability KVM_CAP_RISCV_VM_GPA_SIZE which
You can make it just KVM_CAP_VM_GPA_BITS instead - it's useful on other architectures as well.
Paolo
> can be used by KVM userspace to get guest physical address (GPA) size > (i.e. number of GPA bits) supported for a Guest/VM. > > Signed-off-by: Anup Patel <anup.patel@wdc.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 37589b953bcb..ae5d238607fe 100644 > --- a/arch/riscv/include/asm/kvm_host.h > +++ b/arch/riscv/include/asm/kvm_host.h > @@ -221,6 +221,7 @@ 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_size(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 9ffd0255af43..9b6d6465094f 100644 > --- a/arch/riscv/kvm/mmu.c > +++ b/arch/riscv/kvm/mmu.c > @@ -760,3 +760,8 @@ unsigned long kvm_riscv_stage2_mode(void) > { > return stage2_mode >> HGATP_MODE_SHIFT; > } > + > +int kvm_riscv_stage2_gpa_size(void) > +{ > + return stage2_gpa_bits; > +} > diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c > index fb18af34a4b5..ae97f6929897 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_RISCV_VM_GPA_SIZE: > + r = kvm_riscv_stage2_gpa_size(); > + break; > default: > r = 0; > break; > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 1daa45268de2..dac98df3101d 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_RISCV_VM_GPA_SIZE 207 > > #ifdef KVM_CAP_IRQ_ROUTING > >
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