On 2024/12/23 下午4:50, Huacai Chen wrote:
Hi, Bibo, Is this patch trying to do the same thing as "LoongArch: add hypcall to emulate syscall in kvm" in 4.19?
yes, it is to do so -:) Regards Bibo Mao
Huacai On Mon, Dec 23, 2024 at 4:42 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote: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 loads all six registers to VMM. Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx> --- arch/loongarch/include/asm/kvm_host.h | 1 + arch/loongarch/include/asm/kvm_para.h | 2 ++ arch/loongarch/include/uapi/asm/kvm_para.h | 1 + arch/loongarch/kvm/exit.c | 22 ++++++++++++++++++++++ arch/loongarch/kvm/vcpu.c | 3 +++ 5 files changed, 29 insertions(+) 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/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..1a85cd4fb6a5 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -873,6 +873,28 @@ 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->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..8c46ad1872ee 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -1735,6 +1735,9 @@ 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_write_reg(vcpu, LOONGARCH_GPR_A0, run->hypercall.ret); + update_pc(&vcpu->arch); } if (!vcpu->wants_to_run) base-commit: 48f506ad0b683d3e7e794efa60c5785c4fdc86fa -- 2.39.3
