From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mario Smarduch Subject: Re: [PATCH v6 5/6] arm/arm64: KVM: Introduce armv8 fp/simd vcpu fields and helpers Date: Mon, 11 Jan 2016 16:31:03 -0800 Message-ID: <56944947.2080707@samsung.com> References: <1451166989-3754-1-git-send-email-m.smarduch@samsung.com> <20160110163217.GG30867@cbox> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: marc.zyngier@arm.com, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org To: Christoffer Dall Return-path: In-reply-to: <20160110163217.GG30867@cbox> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org On 1/10/2016 8:32 AM, Christoffer Dall wrote: > On Sat, Dec 26, 2015 at 01:56:29PM -0800, Mario Smarduch wrote: >> Similar to armv7 add helper functions to enable access to fp/smid registers on >> guest entry. Save guest fpexc32_el2 on vcpu_put, check if guest is 32 bit. >> Save guest and restore host registers from host kernel, and check >> if fp/simd registers are dirty, lastly add cptr_el2 vcpu field. >> >> Signed-off-by: Mario Smarduch >> --- >> arch/arm/include/asm/kvm_emulate.h | 12 ++++++++++++ >> arch/arm64/include/asm/kvm_asm.h | 5 +++++ >> arch/arm64/include/asm/kvm_emulate.h | 26 ++++++++++++++++++++++++-- >> arch/arm64/include/asm/kvm_host.h | 12 +++++++++++- >> arch/arm64/kvm/hyp/hyp-entry.S | 26 ++++++++++++++++++++++++++ >> 5 files changed, 78 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h >> index d4d9da1..a434dc5 100644 >> --- a/arch/arm/include/asm/kvm_emulate.h >> +++ b/arch/arm/include/asm/kvm_emulate.h >> @@ -284,6 +284,12 @@ static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> { >> return !(vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11))); >> } >> + >> +static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu) >> +{ >> + return true; >> +} >> +static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) {} >> #else >> static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu) >> { >> @@ -295,6 +301,12 @@ static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> { >> return false; >> } >> + >> +static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu) >> +{ >> + return true; >> +} >> +static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) {} >> #endif >> >> #endif /* __ARM_KVM_EMULATE_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h >> index 52b777b..ddae814 100644 >> --- a/arch/arm64/include/asm/kvm_asm.h >> +++ b/arch/arm64/include/asm/kvm_asm.h >> @@ -48,6 +48,11 @@ extern u64 __vgic_v3_get_ich_vtr_el2(void); >> >> extern u32 __kvm_get_mdcr_el2(void); >> >> +extern void __fpsimd_prepare_fpexc32(void); >> +extern void __fpsimd_save_fpexc32(struct kvm_vcpu *vcpu); >> +extern void __fpsimd_save_state(struct user_fpsimd_state *); >> +extern void __fpsimd_restore_state(struct user_fpsimd_state *); >> + >> #endif >> >> #endif /* __ARM_KVM_ASM_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h >> index ffe8ccf..f8203c7 100644 >> --- a/arch/arm64/include/asm/kvm_emulate.h >> +++ b/arch/arm64/include/asm/kvm_emulate.h >> @@ -299,12 +299,34 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, >> return data; /* Leave LE untouched */ >> } >> >> -static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu) {} >> +static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu) >> +{ >> + return !(vcpu->arch.hcr_el2 & HCR_RW); >> +} >> + >> +static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu) >> +{ >> + /* For 32 bit guest enable access to fp/simd registers */ >> + if (vcpu_guest_is_32bit(vcpu)) >> + vcpu_prepare_fpexc(); >> + >> + vcpu->arch.cptr_el2 = CPTR_EL2_TTA | CPTR_EL2_TFP; >> +} >> + >> static inline void vcpu_restore_host_fpexc(struct kvm_vcpu *vcpu) {} >> >> static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> { >> - return false; >> + return !(vcpu->arch.cptr_el2 & CPTR_EL2_TFP); >> +} >> + >> +static inline void vcpu_restore_host_vfp_state(struct kvm_vcpu *vcpu) >> +{ >> + struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context; >> + struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt; >> + >> + __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs); >> + __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs); >> } >> >> #endif /* __ARM64_KVM_EMULATE_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h >> index bfe4d4e..5d0c256 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -26,6 +26,7 @@ >> #include >> #include >> #include >> +#include >> >> #define __KVM_HAVE_ARCH_INTC_INITIALIZED >> >> @@ -180,6 +181,7 @@ struct kvm_vcpu_arch { >> /* HYP configuration */ >> u64 hcr_el2; >> u32 mdcr_el2; >> + u32 cptr_el2; >> >> /* Exception Information */ >> struct kvm_vcpu_fault_info fault; >> @@ -338,7 +340,15 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} >> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} >> static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} >> >> -static inline void vcpu_restore_host_vfp_state(struct kvm_vcpu *vcpu) {} >> +static inline void vcpu_prepare_fpexc(void) >> +{ >> + kvm_call_hyp(__fpsimd_prepare_fpexc32); >> +} >> + >> +static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) >> +{ >> + kvm_call_hyp(__fpsimd_save_fpexc32, vcpu); >> +} >> >> void kvm_arm_init_debug(void); >> void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); >> diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S >> index 93e8d983..a9235e2 100644 >> --- a/arch/arm64/kvm/hyp/hyp-entry.S >> +++ b/arch/arm64/kvm/hyp/hyp-entry.S >> @@ -164,6 +164,32 @@ ENTRY(__hyp_do_panic) >> eret >> ENDPROC(__hyp_do_panic) >> >> +/** >> + * void __fpsimd_prepare_fpexc32(void) - >> + * We may be entering the guest and set CPTR_EL2.TFP to trap all floating >> + * point register accesses to EL2, however, the ARM manual clearly states >> + * that traps are only taken to EL2 if the operation would not otherwise >> + * trap to EL1. Therefore, always make sure that for 32-bit guests, >> + * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit. >> + */ >> +ENTRY(__fpsimd_prepare_fpexc32) >> + mov x2, #(1 << 30) >> + msr fpexc32_el2, x2 >> + ret >> +ENDPROC(__fpsimd_prepare_fpexc32) > > Why is this code in assembly? > > It feels like you should be able to stick this in switch.c or something? Yeah you're right just reusing code and not integrating into the new structure. > > Also, it's strange to review this patch as duplicating an entire comment > from elsewhere and expecting it to get removed in the next patch, but > ok... Not sure what to do here, the comment is required. Maybe this is a one off you could overlook :) > >> + >> +/** >> + * void __fpsimd_save_fpexc32(void) - >> + * This function restores guest FPEXC to its vcpu context, we call this >> + * function from vcpu_put. >> + */ >> +ENTRY(__fpsimd_save_fpexc32) >> + kern_hyp_va x0 > > the C prototype for this function indicates you don't take any > parameters, but you seem to rely on the vcpu pointer being in x0 for > this? Yes right again should have spotted it. > >> + mrs x2, fpexc32_el2 >> + str x2, [x0, #VCPU_FPEXC32_EL2] >> + ret >> +ENDPROC(__fpsimd_save_fpexc32) >> + >> .macro invalid_vector label, target = __hyp_panic >> .align 2 >> \label: >> -- >> 1.9.1 >> > > Thanks, > -Christoffer > From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.smarduch@samsung.com (Mario Smarduch) Date: Mon, 11 Jan 2016 16:31:03 -0800 Subject: [PATCH v6 5/6] arm/arm64: KVM: Introduce armv8 fp/simd vcpu fields and helpers In-Reply-To: <20160110163217.GG30867@cbox> References: <1451166989-3754-1-git-send-email-m.smarduch@samsung.com> <20160110163217.GG30867@cbox> Message-ID: <56944947.2080707@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 1/10/2016 8:32 AM, Christoffer Dall wrote: > On Sat, Dec 26, 2015 at 01:56:29PM -0800, Mario Smarduch wrote: >> Similar to armv7 add helper functions to enable access to fp/smid registers on >> guest entry. Save guest fpexc32_el2 on vcpu_put, check if guest is 32 bit. >> Save guest and restore host registers from host kernel, and check >> if fp/simd registers are dirty, lastly add cptr_el2 vcpu field. >> >> Signed-off-by: Mario Smarduch >> --- >> arch/arm/include/asm/kvm_emulate.h | 12 ++++++++++++ >> arch/arm64/include/asm/kvm_asm.h | 5 +++++ >> arch/arm64/include/asm/kvm_emulate.h | 26 ++++++++++++++++++++++++-- >> arch/arm64/include/asm/kvm_host.h | 12 +++++++++++- >> arch/arm64/kvm/hyp/hyp-entry.S | 26 ++++++++++++++++++++++++++ >> 5 files changed, 78 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h >> index d4d9da1..a434dc5 100644 >> --- a/arch/arm/include/asm/kvm_emulate.h >> +++ b/arch/arm/include/asm/kvm_emulate.h >> @@ -284,6 +284,12 @@ static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> { >> return !(vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11))); >> } >> + >> +static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu) >> +{ >> + return true; >> +} >> +static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) {} >> #else >> static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu) >> { >> @@ -295,6 +301,12 @@ static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> { >> return false; >> } >> + >> +static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu) >> +{ >> + return true; >> +} >> +static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) {} >> #endif >> >> #endif /* __ARM_KVM_EMULATE_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h >> index 52b777b..ddae814 100644 >> --- a/arch/arm64/include/asm/kvm_asm.h >> +++ b/arch/arm64/include/asm/kvm_asm.h >> @@ -48,6 +48,11 @@ extern u64 __vgic_v3_get_ich_vtr_el2(void); >> >> extern u32 __kvm_get_mdcr_el2(void); >> >> +extern void __fpsimd_prepare_fpexc32(void); >> +extern void __fpsimd_save_fpexc32(struct kvm_vcpu *vcpu); >> +extern void __fpsimd_save_state(struct user_fpsimd_state *); >> +extern void __fpsimd_restore_state(struct user_fpsimd_state *); >> + >> #endif >> >> #endif /* __ARM_KVM_ASM_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h >> index ffe8ccf..f8203c7 100644 >> --- a/arch/arm64/include/asm/kvm_emulate.h >> +++ b/arch/arm64/include/asm/kvm_emulate.h >> @@ -299,12 +299,34 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, >> return data; /* Leave LE untouched */ >> } >> >> -static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu) {} >> +static inline bool vcpu_guest_is_32bit(struct kvm_vcpu *vcpu) >> +{ >> + return !(vcpu->arch.hcr_el2 & HCR_RW); >> +} >> + >> +static inline void vcpu_trap_vfp_enable(struct kvm_vcpu *vcpu) >> +{ >> + /* For 32 bit guest enable access to fp/simd registers */ >> + if (vcpu_guest_is_32bit(vcpu)) >> + vcpu_prepare_fpexc(); >> + >> + vcpu->arch.cptr_el2 = CPTR_EL2_TTA | CPTR_EL2_TFP; >> +} >> + >> static inline void vcpu_restore_host_fpexc(struct kvm_vcpu *vcpu) {} >> >> static inline bool vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> { >> - return false; >> + return !(vcpu->arch.cptr_el2 & CPTR_EL2_TFP); >> +} >> + >> +static inline void vcpu_restore_host_vfp_state(struct kvm_vcpu *vcpu) >> +{ >> + struct kvm_cpu_context *host_ctxt = vcpu->arch.host_cpu_context; >> + struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt; >> + >> + __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs); >> + __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs); >> } >> >> #endif /* __ARM64_KVM_EMULATE_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h >> index bfe4d4e..5d0c256 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -26,6 +26,7 @@ >> #include >> #include >> #include >> +#include >> >> #define __KVM_HAVE_ARCH_INTC_INITIALIZED >> >> @@ -180,6 +181,7 @@ struct kvm_vcpu_arch { >> /* HYP configuration */ >> u64 hcr_el2; >> u32 mdcr_el2; >> + u32 cptr_el2; >> >> /* Exception Information */ >> struct kvm_vcpu_fault_info fault; >> @@ -338,7 +340,15 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} >> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} >> static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} >> >> -static inline void vcpu_restore_host_vfp_state(struct kvm_vcpu *vcpu) {} >> +static inline void vcpu_prepare_fpexc(void) >> +{ >> + kvm_call_hyp(__fpsimd_prepare_fpexc32); >> +} >> + >> +static inline void vcpu_save_fpexc(struct kvm_vcpu *vcpu) >> +{ >> + kvm_call_hyp(__fpsimd_save_fpexc32, vcpu); >> +} >> >> void kvm_arm_init_debug(void); >> void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); >> diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S >> index 93e8d983..a9235e2 100644 >> --- a/arch/arm64/kvm/hyp/hyp-entry.S >> +++ b/arch/arm64/kvm/hyp/hyp-entry.S >> @@ -164,6 +164,32 @@ ENTRY(__hyp_do_panic) >> eret >> ENDPROC(__hyp_do_panic) >> >> +/** >> + * void __fpsimd_prepare_fpexc32(void) - >> + * We may be entering the guest and set CPTR_EL2.TFP to trap all floating >> + * point register accesses to EL2, however, the ARM manual clearly states >> + * that traps are only taken to EL2 if the operation would not otherwise >> + * trap to EL1. Therefore, always make sure that for 32-bit guests, >> + * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit. >> + */ >> +ENTRY(__fpsimd_prepare_fpexc32) >> + mov x2, #(1 << 30) >> + msr fpexc32_el2, x2 >> + ret >> +ENDPROC(__fpsimd_prepare_fpexc32) > > Why is this code in assembly? > > It feels like you should be able to stick this in switch.c or something? Yeah you're right just reusing code and not integrating into the new structure. > > Also, it's strange to review this patch as duplicating an entire comment > from elsewhere and expecting it to get removed in the next patch, but > ok... Not sure what to do here, the comment is required. Maybe this is a one off you could overlook :) > >> + >> +/** >> + * void __fpsimd_save_fpexc32(void) - >> + * This function restores guest FPEXC to its vcpu context, we call this >> + * function from vcpu_put. >> + */ >> +ENTRY(__fpsimd_save_fpexc32) >> + kern_hyp_va x0 > > the C prototype for this function indicates you don't take any > parameters, but you seem to rely on the vcpu pointer being in x0 for > this? Yes right again should have spotted it. > >> + mrs x2, fpexc32_el2 >> + str x2, [x0, #VCPU_FPEXC32_EL2] >> + ret >> +ENDPROC(__fpsimd_save_fpexc32) >> + >> .macro invalid_vector label, target = __hyp_panic >> .align 2 >> \label: >> -- >> 1.9.1 >> > > Thanks, > -Christoffer >