On 2024/6/23 下午6:11, Huacai Chen wrote:
Hi, Bibo, On Mon, May 27, 2024 at 3:46 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:Loongson Binary Translation (LBT) is used to accelerate binary translation, which contains 4 scratch registers (scr0 to scr3), x86/ARM eflags (eflags) and x87 fpu stack pointer (ftop). Like FPU extension, here late enabling method is used for LBT. LBT context is saved/restored on vcpu context switch path. Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx> --- arch/loongarch/include/asm/kvm_host.h | 8 ++++ arch/loongarch/include/asm/kvm_vcpu.h | 10 +++++ arch/loongarch/kvm/exit.c | 9 ++++ arch/loongarch/kvm/vcpu.c | 59 ++++++++++++++++++++++++++- 4 files changed, 85 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h index 2eb2f7572023..88023ab59486 100644 --- a/arch/loongarch/include/asm/kvm_host.h +++ b/arch/loongarch/include/asm/kvm_host.h @@ -133,6 +133,7 @@ enum emulation_result { #define KVM_LARCH_LASX (0x1 << 2) #define KVM_LARCH_SWCSR_LATEST (0x1 << 3) #define KVM_LARCH_HWCSR_USABLE (0x1 << 4) +#define KVM_LARCH_LBT (0x1 << 5) struct kvm_vcpu_arch { /* @@ -166,6 +167,7 @@ struct kvm_vcpu_arch { /* FPU state */ struct loongarch_fpu fpu FPU_ALIGN; + struct loongarch_lbt lbt; /* CSR state */ struct loongarch_csrs *csr; @@ -235,6 +237,12 @@ static inline bool kvm_guest_has_lasx(struct kvm_vcpu_arch *arch) return arch->cpucfg[2] & CPUCFG2_LASX; } +static inline bool kvm_guest_has_lbt(struct kvm_vcpu_arch *arch) +{ + return arch->cpucfg[2] & (CPUCFG2_X86BT | CPUCFG2_ARMBT + | CPUCFG2_MIPSBT); +} + /* 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 d7e51300a89f..ec46009be29b 100644 --- a/arch/loongarch/include/asm/kvm_vcpu.h +++ b/arch/loongarch/include/asm/kvm_vcpu.h @@ -75,6 +75,16 @@ static inline void kvm_save_lasx(struct loongarch_fpu *fpu) { } static inline void kvm_restore_lasx(struct loongarch_fpu *fpu) { } #endif +#ifdef CONFIG_CPU_HAS_LBT +int kvm_own_lbt(struct kvm_vcpu *vcpu); +#else +static inline int kvm_own_lbt(struct kvm_vcpu *vcpu) { return -EINVAL; } +static inline void kvm_lose_lbt(struct kvm_vcpu *vcpu) { } +static inline void kvm_enable_lbt_fpu(struct kvm_vcpu *vcpu, + unsigned long fcsr) { } +static inline void kvm_check_fcsr(struct kvm_vcpu *vcpu) { } +#endifIt is better to keep symmetry here. That means also declare kvm_lose_lbt for CONFIG_CPU_HAS_LBT, and move the last two functions to .c because they are static.
Sure, will do in this way in next version. Regards Bibo Mao
+ void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz); void kvm_reset_timer(struct kvm_vcpu *vcpu); void kvm_save_timer(struct kvm_vcpu *vcpu); diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index e2abd97fb13f..e1bd81d27fd8 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -835,6 +835,14 @@ static int kvm_handle_hypercall(struct kvm_vcpu *vcpu) return ret; } +static int kvm_handle_lbt_disabled(struct kvm_vcpu *vcpu) +{ + if (kvm_own_lbt(vcpu)) + kvm_queue_exception(vcpu, EXCCODE_INE, 0); + + return RESUME_GUEST; +} + /* * LoongArch KVM callback handling for unimplemented guest exiting */ @@ -867,6 +875,7 @@ static exit_handle_fn kvm_fault_tables[EXCCODE_INT_START] = { [EXCCODE_LASXDIS] = kvm_handle_lasx_disabled, [EXCCODE_GSPR] = kvm_handle_gspr, [EXCCODE_HVC] = kvm_handle_hypercall, + [EXCCODE_BTDIS] = kvm_handle_lbt_disabled, }; int kvm_handle_fault(struct kvm_vcpu *vcpu, int fault) diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 382796f1d3e6..8f80d1a2dcbb 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -6,6 +6,7 @@ #include <linux/kvm_host.h> #include <linux/entry-kvm.h> #include <asm/fpu.h> +#include <asm/lbt.h> #include <asm/loongarch.h> #include <asm/setup.h> #include <asm/time.h> @@ -952,12 +953,64 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) return 0; } +#ifdef CONFIG_CPU_HAS_LBT +int kvm_own_lbt(struct kvm_vcpu *vcpu) +{ + if (!kvm_guest_has_lbt(&vcpu->arch)) + return -EINVAL; + + preempt_disable(); + set_csr_euen(CSR_EUEN_LBTEN); + + _restore_lbt(&vcpu->arch.lbt); + vcpu->arch.aux_inuse |= KVM_LARCH_LBT; + preempt_enable(); + return 0; +} + +static void kvm_lose_lbt(struct kvm_vcpu *vcpu) +{ + preempt_disable(); + if (vcpu->arch.aux_inuse & KVM_LARCH_LBT) { + _save_lbt(&vcpu->arch.lbt); + clear_csr_euen(CSR_EUEN_LBTEN); + vcpu->arch.aux_inuse &= ~KVM_LARCH_LBT; + } + preempt_enable(); +} + +static void kvm_enable_lbt_fpu(struct kvm_vcpu *vcpu, unsigned long fcsr)It is better to rename it to kvm_own_lbt_tm().+{ + /* + * if TM is enabled, top register save/restore will + * cause lbt exception, here enable lbt in advance + */ + if (fcsr & FPU_CSR_TM) + kvm_own_lbt(vcpu); +} + +static void kvm_check_fcsr(struct kvm_vcpu *vcpu) +{ + unsigned long fcsr; + + if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) + if (!(vcpu->arch.aux_inuse & KVM_LARCH_LBT)) {The condition can be simplified " if (vcpu->arch.aux_inuse & (KVM_LARCH_FPU|KVM_LARCH_LBT) == KVM_LARCH_FPU)"+ fcsr = read_fcsr(LOONGARCH_FCSR0); + kvm_enable_lbt_fpu(vcpu, fcsr); + } +} +#endif + /* Enable FPU and restore context */ void kvm_own_fpu(struct kvm_vcpu *vcpu) { preempt_disable(); - /* Enable FPU */ + /* + * Enable FPU for guest + * We set FR and FRE according to guest context + */ + kvm_enable_lbt_fpu(vcpu, vcpu->arch.fpu.fcsr); set_csr_euen(CSR_EUEN_FPEN); kvm_restore_fpu(&vcpu->arch.fpu); @@ -977,6 +1030,7 @@ int kvm_own_lsx(struct kvm_vcpu *vcpu) preempt_disable(); /* Enable LSX for guest */ + kvm_enable_lbt_fpu(vcpu, vcpu->arch.fpu.fcsr); set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN); switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) { case KVM_LARCH_FPU: @@ -1011,6 +1065,7 @@ int kvm_own_lasx(struct kvm_vcpu *vcpu) preempt_disable(); + kvm_enable_lbt_fpu(vcpu, vcpu->arch.fpu.fcsr); set_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN | CSR_EUEN_LASXEN); switch (vcpu->arch.aux_inuse & (KVM_LARCH_FPU | KVM_LARCH_LSX)) { case KVM_LARCH_LSX: @@ -1042,6 +1097,7 @@ void kvm_lose_fpu(struct kvm_vcpu *vcpu) { preempt_disable(); + kvm_check_fcsr(vcpu); if (vcpu->arch.aux_inuse & KVM_LARCH_LASX) { kvm_save_lasx(&vcpu->arch.fpu); vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU | KVM_LARCH_LASX); @@ -1064,6 +1120,7 @@ void kvm_lose_fpu(struct kvm_vcpu *vcpu) /* Disable FPU */ clear_csr_euen(CSR_EUEN_FPEN); } + kvm_lose_lbt(vcpu); preempt_enable(); } -- 2.39.3
