Some VMMs provides special hypercall service in usermode, KVM need
not handle the usermode hypercall service and pass it to VMM and
let VMM handle it.
Here new code KVM_HCALL_CODE_USER is added for user-mode hypercall
service, KVM lets all six registers visiable to VMM.
Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
v1 ... v2:
1. Add function kvm_complete_user_service() when finish hypercall
in user-mode VMM and continue to run.
2. Add hypercall_exits stat information.
---
arch/loongarch/include/asm/kvm_host.h | 1 +
arch/loongarch/include/asm/kvm_para.h | 2 ++
arch/loongarch/include/asm/kvm_vcpu.h | 1 +
arch/loongarch/include/uapi/asm/kvm_para.h | 1 +
arch/loongarch/kvm/exit.c | 30 ++++++++++++++++++++++
arch/loongarch/kvm/vcpu.c | 3 ++-
6 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 7b8367c39da8..590982cd986e 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -162,6 +162,7 @@ enum emulation_result {
#define LOONGARCH_PV_FEAT_UPDATED BIT_ULL(63)
#define LOONGARCH_PV_FEAT_MASK (BIT(KVM_FEATURE_IPI) | \
BIT(KVM_FEATURE_STEAL_TIME) | \
+ BIT(KVM_FEATURE_USER_HCALL) | \
BIT(KVM_FEATURE_VIRT_EXTIOI))
struct kvm_vcpu_arch {
diff --git a/arch/loongarch/include/asm/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h
index c4e84227280d..d3c00de484f6 100644
--- a/arch/loongarch/include/asm/kvm_para.h
+++ b/arch/loongarch/include/asm/kvm_para.h
@@ -13,12 +13,14 @@
#define KVM_HCALL_CODE_SERVICE 0
#define KVM_HCALL_CODE_SWDBG 1
+#define KVM_HCALL_CODE_USER 2
#define KVM_HCALL_SERVICE HYPERCALL_ENCODE(HYPERVISOR_KVM, KVM_HCALL_CODE_SERVICE)
#define KVM_HCALL_FUNC_IPI 1
#define KVM_HCALL_FUNC_NOTIFY 2
#define KVM_HCALL_SWDBG HYPERCALL_ENCODE(HYPERVISOR_KVM, KVM_HCALL_CODE_SWDBG)
+#define KVM_HCALL_USER_SERVICE HYPERCALL_ENCODE(HYPERVISOR_KVM, KVM_HCALL_CODE_USER)
/*
* LoongArch hypercall return code
diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
index d7e8f7d50ee0..2c349f961bfb 100644
--- a/arch/loongarch/include/asm/kvm_vcpu.h
+++ b/arch/loongarch/include/asm/kvm_vcpu.h
@@ -43,6 +43,7 @@ int kvm_emu_mmio_read(struct kvm_vcpu *vcpu, larch_inst inst);
int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst);
int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run);
int kvm_complete_iocsr_read(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_complete_user_service(struct kvm_vcpu *vcpu, struct kvm_run *run);
int kvm_emu_idle(struct kvm_vcpu *vcpu);
int kvm_pending_timer(struct kvm_vcpu *vcpu);
int kvm_handle_fault(struct kvm_vcpu *vcpu, int fault);
diff --git a/arch/loongarch/include/uapi/asm/kvm_para.h b/arch/loongarch/include/uapi/asm/kvm_para.h
index b0604aa9b4bb..76d802ef01ce 100644
--- a/arch/loongarch/include/uapi/asm/kvm_para.h
+++ b/arch/loongarch/include/uapi/asm/kvm_para.h
@@ -17,5 +17,6 @@
#define KVM_FEATURE_STEAL_TIME 2
/* BIT 24 - 31 are features configurable by user space vmm */
#define KVM_FEATURE_VIRT_EXTIOI 24
+#define KVM_FEATURE_USER_HCALL 25
#endif /* _UAPI_ASM_KVM_PARA_H */
diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index a7893bd01e73..70b5ed1241c4 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -538,6 +538,13 @@ int kvm_complete_mmio_read(struct kvm_vcpu *vcpu, struct kvm_run *run)
return er;
}
+int kvm_complete_user_service(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ update_pc(&vcpu->arch);
+ kvm_write_reg(vcpu, LOONGARCH_GPR_A0, run->hypercall.ret);
+ return 0;
+}
+
int kvm_emu_mmio_write(struct kvm_vcpu *vcpu, larch_inst inst)
{
int idx, ret;
@@ -873,6 +880,29 @@ static int kvm_handle_hypercall(struct kvm_vcpu *vcpu)
vcpu->stat.hypercall_exits++;
kvm_handle_service(vcpu);
break;
+ case KVM_HCALL_USER_SERVICE:
+ if (!kvm_guest_has_pv_feature(vcpu, KVM_FEATURE_USER_HCALL)) {
+ kvm_write_reg(vcpu, LOONGARCH_GPR_A0, KVM_HCALL_INVALID_CODE);
+ break;
+ }
+
+ vcpu->stat.hypercall_exits++;
+ vcpu->run->exit_reason = KVM_EXIT_HYPERCALL;
+ vcpu->run->hypercall.nr = KVM_HCALL_USER_SERVICE;
+ vcpu->run->hypercall.args[0] = kvm_read_reg(vcpu, LOONGARCH_GPR_A0);
+ vcpu->run->hypercall.args[1] = kvm_read_reg(vcpu, LOONGARCH_GPR_A1);
+ vcpu->run->hypercall.args[2] = kvm_read_reg(vcpu, LOONGARCH_GPR_A2);
+ vcpu->run->hypercall.args[3] = kvm_read_reg(vcpu, LOONGARCH_GPR_A3);
+ vcpu->run->hypercall.args[4] = kvm_read_reg(vcpu, LOONGARCH_GPR_A4);
+ vcpu->run->hypercall.args[5] = kvm_read_reg(vcpu, LOONGARCH_GPR_A5);
+ vcpu->run->hypercall.flags = 0;
+ /*
+ * Set invalid return value by default
+ * Need user-mode VMM modify it
+ */
+ vcpu->run->hypercall.ret = KVM_HCALL_INVALID_CODE;
+ ret = RESUME_HOST;
+ break;
case KVM_HCALL_SWDBG:
/* KVM_HCALL_SWDBG only in effective when SW_BP is enabled */
if (vcpu->guest_debug & KVM_GUESTDBG_SW_BP_MASK) {
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index d18a4a270415..888480a5bc25 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -1735,7 +1735,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
if (run->exit_reason == KVM_EXIT_LOONGARCH_IOCSR) {
if (!run->iocsr_io.is_write)
kvm_complete_iocsr_read(vcpu, run);
- }
+ } else if (run->exit_reason == KVM_EXIT_HYPERCALL)
+ kvm_complete_user_service(vcpu, run);
if (!vcpu->wants_to_run)
return r;
base-commit: fc033cf25e612e840e545f8d5ad2edd6ba613ed5
--
2.39.3
