Messages in this thread | | | Subject | Re: [PATCH v1 1/2] LoongArch: KVM: Add lsx support | From | zhaotianrui <> | Date | Tue, 21 Nov 2023 17:56:33 +0800 |
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在 2023/11/16 下午3:15, WANG Xuerui 写道: > > On 11/15/23 17:19, Tianrui Zhao wrote: >> This patch adds LSX support for LoongArch KVM. The LSX means >> LoongArch 128-bits vector instruction. > Maybe we don't need to explain what "LSX" is; people working on > LoongArch kernel should already know this through the kernel docs and > the various occurrences in the code. Thanks, I will remove the explain about "LSX, LASX". >> There will be LSX exception in KVM when guest use the LSX >> instruction. KVM will enable LSX and restore the vector >> registers for guest then return to guest to continue running. >> > One more extra line that should get removed. Thanks, I will remove the extra line. >> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn> >> --- >> arch/loongarch/include/asm/kvm_host.h | 6 ++++ >> arch/loongarch/include/asm/kvm_vcpu.h | 12 +++++++ >> arch/loongarch/kvm/exit.c | 18 ++++++++++ >> arch/loongarch/kvm/switch.S | 22 +++++++++++++ >> arch/loongarch/kvm/trace.h | 4 ++- >> arch/loongarch/kvm/vcpu.c | 47 +++++++++++++++++++++++++-- >> 6 files changed, 105 insertions(+), 4 deletions(-) >> >> diff --git a/arch/loongarch/include/asm/kvm_host.h >> b/arch/loongarch/include/asm/kvm_host.h >> index 11328700d4..6c65c25169 100644 >> --- a/arch/loongarch/include/asm/kvm_host.h >> +++ b/arch/loongarch/include/asm/kvm_host.h >> @@ -94,6 +94,7 @@ enum emulation_result { >> #define KVM_LARCH_FPU (0x1 << 0) >> #define KVM_LARCH_SWCSR_LATEST (0x1 << 1) >> #define KVM_LARCH_HWCSR_USABLE (0x1 << 2) >> +#define KVM_LARCH_LSX (0x1 << 3) >> struct kvm_vcpu_arch { >> /* >> @@ -175,6 +176,11 @@ static inline void writel_sw_gcsr(struct >> loongarch_csrs *csr, int reg, unsigned >> csr->csrs[reg] = val; >> } >> +static inline bool kvm_guest_has_lsx(struct kvm_vcpu_arch *arch) >> +{ >> + return arch->cpucfg[2] & CPUCFG2_LSX; >> +} >> + >> /* Debug: dump vcpu state */ >> int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu); >> diff --git a/arch/loongarch/include/asm/kvm_vcpu.h >> b/arch/loongarch/include/asm/kvm_vcpu.h >> index 553cfa2b2b..c629771e12 100644 >> --- a/arch/loongarch/include/asm/kvm_vcpu.h >> +++ b/arch/loongarch/include/asm/kvm_vcpu.h >> @@ -55,6 +55,18 @@ void kvm_save_fpu(struct loongarch_fpu *fpu); >> void kvm_restore_fpu(struct loongarch_fpu *fpu); >> void kvm_restore_fcsr(struct loongarch_fpu *fpu); >> +#ifdef CONFIG_CPU_HAS_LSX >> +void kvm_own_lsx(struct kvm_vcpu *vcpu); >> +void kvm_save_lsx(struct loongarch_fpu *fpu); >> +void kvm_restore_lsx(struct loongarch_fpu *fpu); >> +void kvm_restore_lsx_upper(struct loongarch_fpu *fpu); >> +#else >> +static inline void kvm_own_lsx(struct kvm_vcpu *vcpu) { } >> +static inline void kvm_save_lsx(struct loongarch_fpu *fpu) { } >> +static inline void kvm_restore_lsx(struct loongarch_fpu *fpu) { } >> +static inline void kvm_restore_lsx_upper(struct loongarch_fpu *fpu) { } >> +#endif >> + >> void kvm_acquire_timer(struct kvm_vcpu *vcpu); >> void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz); >> void kvm_reset_timer(struct kvm_vcpu *vcpu); >> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c >> index ce8de3fa47..1b1c58ccc8 100644 >> --- a/arch/loongarch/kvm/exit.c >> +++ b/arch/loongarch/kvm/exit.c >> @@ -659,6 +659,23 @@ static int kvm_handle_fpu_disabled(struct >> kvm_vcpu *vcpu) >> return RESUME_GUEST; >> } >> +/* >> + * kvm_handle_lsx_disabled() - Guest used LSX while disabled in root. >> + * @vcpu: Virtual CPU context. >> + * >> + * Handle when the guest attempts to use LSX when it is disabled in >> the root >> + * context. >> + */ >> +static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu) >> +{ >> + if (!kvm_guest_has_lsx(&vcpu->arch)) >> + kvm_queue_exception(vcpu, EXCCODE_INE, 0); >> + else >> + kvm_own_lsx(vcpu); >> + >> + return RESUME_GUEST; >> +} >> + >> /* >> * LoongArch KVM callback handling for unimplemented guest exiting >> */ >> @@ -687,6 +704,7 @@ static exit_handle_fn >> kvm_fault_tables[EXCCODE_INT_START] = { >> [EXCCODE_TLBS] = kvm_handle_write_fault, >> [EXCCODE_TLBM] = kvm_handle_write_fault, >> [EXCCODE_FPDIS] = kvm_handle_fpu_disabled, >> + [EXCCODE_LSXDIS] = kvm_handle_lsx_disabled, >> [EXCCODE_GSPR] = kvm_handle_gspr, >> }; >> diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S >> index 0ed9040307..32ba092a44 100644 >> --- a/arch/loongarch/kvm/switch.S >> +++ b/arch/loongarch/kvm/switch.S >> @@ -245,6 +245,28 @@ SYM_FUNC_START(kvm_restore_fpu) >> jr ra >> SYM_FUNC_END(kvm_restore_fpu) >> +#ifdef CONFIG_CPU_HAS_LSX >> +SYM_FUNC_START(kvm_save_lsx) >> + fpu_save_csr a0 t1 >> + fpu_save_cc a0 t1 t2 >> + lsx_save_data a0 t1 >> + jirl zero, ra, 0 > "jr ra" for consistency (e.g. with the function immediately above); > similarly for other such usages. Thanks, I will use "jr ra" there.
Tianrui Zhao >> +SYM_FUNC_END(kvm_save_lsx) >> + >> +SYM_FUNC_START(kvm_restore_lsx) >> + lsx_restore_data a0 t1 >> + fpu_restore_cc a0 t1 t2 >> + fpu_restore_csr a0 t1 >> + jirl zero, ra, 0 >> +SYM_FUNC_END(kvm_restore_lsx) >> + >> +SYM_FUNC_START(kvm_restore_lsx_upper) >> + lsx_restore_all_upper a0 t0 t1 >> + >> + jirl zero, ra, 0 >> +SYM_FUNC_END(kvm_restore_lsx_upper) >> +#endif >> + >> .section ".rodata" >> SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry) >> SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - >> kvm_enter_guest) >> diff --git a/arch/loongarch/kvm/trace.h b/arch/loongarch/kvm/trace.h >> index a1e35d6554..7da4e230e8 100644 >> --- a/arch/loongarch/kvm/trace.h >> +++ b/arch/loongarch/kvm/trace.h >> @@ -102,6 +102,7 @@ TRACE_EVENT(kvm_exit_gspr, >> #define KVM_TRACE_AUX_DISCARD 4 >> #define KVM_TRACE_AUX_FPU 1 >> +#define KVM_TRACE_AUX_LSX 2 >> #define kvm_trace_symbol_aux_op \ >> { KVM_TRACE_AUX_SAVE, "save" }, \ >> @@ -111,7 +112,8 @@ TRACE_EVENT(kvm_exit_gspr, >> { KVM_TRACE_AUX_DISCARD, "discard" } >> #define kvm_trace_symbol_aux_state \ >> - { KVM_TRACE_AUX_FPU, "FPU" } >> + { KVM_TRACE_AUX_FPU, "FPU" }, \ >> + { KVM_TRACE_AUX_LSX, "LSX" } >> TRACE_EVENT(kvm_aux, >> TP_PROTO(struct kvm_vcpu *vcpu, unsigned int op, >> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c >> index 73d0c2b9c1..f0bb583353 100644 >> --- a/arch/loongarch/kvm/vcpu.c >> +++ b/arch/loongarch/kvm/vcpu.c >> @@ -378,9 +378,13 @@ static int kvm_set_one_reg(struct kvm_vcpu *vcpu, >> break; >> case KVM_REG_LOONGARCH_CPUCFG: >> id = KVM_GET_IOC_CPUCFG_IDX(reg->id); >> - if (id >= 0 && id < KVM_MAX_CPUCFG_REGS) >> + if (id >= 0 && id < KVM_MAX_CPUCFG_REGS) { >> vcpu->arch.cpucfg[id] = (u32)v; >> - else >> + if (id == 2 && v & CPUCFG2_LSX && !cpu_has_lsx) { >> + vcpu->arch.cpucfg[id] &= ~CPUCFG2_LSX; >> + ret = -EINVAL; >> + } >> + } else >> ret = -EINVAL; >> break; >> case KVM_REG_LOONGARCH_KVM: >> @@ -561,12 +565,49 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu) >> preempt_enable(); >> } >> +#ifdef CONFIG_CPU_HAS_LSX >> +/* Enable LSX for guest and restore context */ >> +void kvm_own_lsx(struct kvm_vcpu *vcpu) >> +{ >> + preempt_disable(); >> + >> + /* Enable LSX for guest */ >> + set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN); >> + switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) { >> + case KVM_LARCH_FPU: >> + /* >> + * Guest FPU state already loaded, >> + * only restore upper LSX state >> + */ >> + kvm_restore_lsx_upper(&vcpu->arch.fpu); >> + break; >> + default: >> + /* Neither FP or LSX already active, >> + * restore full LSX state >> + */ >> + kvm_restore_lsx(&vcpu->arch.fpu); >> + break; >> + } >> + >> + trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LSX); >> + vcpu->arch.aux_inuse |= KVM_LARCH_LSX | KVM_LARCH_FPU; >> + preempt_enable(); >> +} >> +#endif >> + >> /* Save context and disable FPU */ >> void kvm_lose_fpu(struct kvm_vcpu *vcpu) >> { >> preempt_disable(); >> - if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) { >> + if (vcpu->arch.aux_inuse & KVM_LARCH_LSX) { >> + kvm_save_lsx(&vcpu->arch.fpu); >> + vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU); >> + trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_LSX); >> + >> + /* Disable LSX & FPU */ >> + clear_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN); >> + } else if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) { >> kvm_save_fpu(&vcpu->arch.fpu); >> vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU; >> trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU); >
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