lkml.org 
[lkml]   [2021]   [Dec]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4 2/4] RISC-V: KVM: Add VM capability to allow userspace get GPA bits
Date
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

--
2.25.1
\
 
 \ /
  Last update: 2021-12-24 08:37    [W:0.060 / U:2.416 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site