| Message ID | 1449450434-2929-3-git-send-email-m.smarduch@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Dec 06, 2015 at 05:07:13PM -0800, Mario Smarduch wrote: > This patch tracks armv7 fp/simd hardware state with hcptr register. > On vcpu_load saves host fpexc, enables FP access, and sets trapping > on fp/simd access. On first fp/simd access trap to handler to save host and > restore guest context, clear trapping bits to enable vcpu lazy mode. On > vcpu_put if trap bits are cleared save guest and restore host context and > always restore host fpexc. > > Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> > --- > arch/arm/include/asm/kvm_emulate.h | 50 ++++++++++++++++++++++++++++++++++++ > arch/arm/include/asm/kvm_host.h | 1 + > arch/arm/kvm/Makefile | 2 +- > arch/arm/kvm/arm.c | 13 ++++++++++ > arch/arm/kvm/fpsimd_switch.S | 46 +++++++++++++++++++++++++++++++++ > arch/arm/kvm/interrupts.S | 32 +++++------------------ > arch/arm/kvm/interrupts_head.S | 33 ++++++++++-------------- > arch/arm64/include/asm/kvm_emulate.h | 9 +++++++ > arch/arm64/include/asm/kvm_host.h | 1 + > 9 files changed, 142 insertions(+), 45 deletions(-) > create mode 100644 arch/arm/kvm/fpsimd_switch.S > > diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h > index a9c80a2..3de11a2 100644 > --- a/arch/arm/include/asm/kvm_emulate.h > +++ b/arch/arm/include/asm/kvm_emulate.h > @@ -243,4 +243,54 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, > } > } > > +#ifdef CONFIG_VFPv3 > +/* Called from vcpu_load - save fpexc and enable guest access to fp/simd unit */ are you really enabling guest access here or just fiddling with fpexc to ensure you trap accesses to hyp ? > +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) > +{ > + u32 fpexc; > + > + asm volatile( > + "mrc p10, 7, %0, cr8, cr0, 0\n" > + "str %0, [%1]\n" > + "mov %0, #(1 << 30)\n" > + "mcr p10, 7, %0, cr8, cr0, 0\n" > + "isb\n" why do you need an ISB here? won't there be an implicit one from the HVC call later before you need this to take effect? > + : "+r" (fpexc) > + : "r" (&vcpu->arch.host_fpexc) > + ); this whole bit can be rewritten something like: fpexc = fmrx(FPEXC); vcpu->arch.host_fpexc = fpexc; fpexc |= FPEXC_EN; fmxr(FPEXC, fpexc); > +} > + > +/* Called from vcpu_put - restore host fpexc */ > +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) > +{ > + asm volatile( > + "mcr p10, 7, %0, cr8, cr0, 0\n" > + : > + : "r" (vcpu->arch.host_fpexc) > + ); similarly here > +} > + > +/* If trap bits are reset then fp/simd registers are dirty */ > +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) > +{ > + return !!(~vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11))); this looks complicated, how about: return !(vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11))); > +} > + > +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) > +{ > + vcpu->arch.hcptr |= (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)); > +} > +#else > +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) {} > +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {} > +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) > +{ > + return false; > +} > +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) > +{ > + vcpu->arch.hcptr = HCPTR_TTA; > +} > +#endif > + > #endif /* __ARM_KVM_EMULATE_H__ */ > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index 09bb1f2..ecc883a 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -227,6 +227,7 @@ int kvm_perf_teardown(void); > void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); > > struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr); > +void kvm_restore_host_vfp_state(struct kvm_vcpu *); > > static inline void kvm_arch_hardware_disable(void) {} > static inline void kvm_arch_hardware_unsetup(void) {} > diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile > index c5eef02c..411b3e4 100644 > --- a/arch/arm/kvm/Makefile > +++ b/arch/arm/kvm/Makefile > @@ -19,7 +19,7 @@ kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o $(KVM)/vf > > obj-y += kvm-arm.o init.o interrupts.o > obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o > -obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o > +obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o fpsimd_switch.o > obj-y += $(KVM)/arm/vgic.o > obj-y += $(KVM)/arm/vgic-v2.o > obj-y += $(KVM)/arm/vgic-v2-emul.o > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index dc017ad..1de07ab 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -291,10 +291,23 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > vcpu->arch.host_cpu_context = this_cpu_ptr(kvm_host_cpu_state); > > kvm_arm_set_running_vcpu(vcpu); > + > + /* Save and enable FPEXC before we load guest context */ > + kvm_enable_vcpu_fpexc(vcpu); hmmm, not really sure the 'enable' part of this name is the right choice when looking at this. kvm_prepare_vcpu_fpexc ? > + > + /* reset hyp cptr register to trap on tracing and vfp/simd access*/ > + vcpu_reset_cptr(vcpu); alternatively you could combine the two functions above into a single function called something like "vcpu_trap_vfp_enable()" or "vcpu_load_configure_vfp()" (I sort of feel like we have reserved the _reset_ namespace for stuff we actually do at VCPU reset.) > } > > void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) > { > + /* If the fp/simd registers are dirty save guest, restore host. */ > + if (kvm_vcpu_vfp_isdirty(vcpu)) > + kvm_restore_host_vfp_state(vcpu); > + > + /* Restore host FPEXC trashed in vcpu_load */ > + kvm_restore_host_fpexc(vcpu); > + > /* > * The arch-generic KVM code expects the cpu field of a vcpu to be -1 > * if the vcpu is no longer assigned to a cpu. This is used for the > diff --git a/arch/arm/kvm/fpsimd_switch.S b/arch/arm/kvm/fpsimd_switch.S > new file mode 100644 > index 0000000..d297c54 > --- /dev/null > +++ b/arch/arm/kvm/fpsimd_switch.S > @@ -0,0 +1,46 @@ > +/* > + * Copyright (C) 2012 - Virtual Open Systems and Columbia University > + * Author: Christoffer Dall <c.dall@virtualopensystems.com> Not quite, this is new code, so you should just claim copyright and authorship I believe. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License, version 2, as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > +#include <linux/linkage.h> > +#include <linux/const.h> > +#include <asm/unified.h> > +#include <asm/page.h> > +#include <asm/ptrace.h> > +#include <asm/asm-offsets.h> > +#include <asm/kvm_asm.h> > +#include <asm/kvm_arm.h> > +#include <asm/vfpmacros.h> > +#include "interrupts_head.S" > + > + .text > +/** > + * void kvm_restore_host_vfp_state(struct vcpu *vcpu) - > + * This function is called from host to save the guest, and restore host > + * fp/simd hardware context. It's placed outside of hyp start/end region. > + */ > +ENTRY(kvm_restore_host_vfp_state) > +#ifdef CONFIG_VFPv3 > + push {r4-r7} > + > + add r7, r0, #VCPU_VFP_GUEST > + store_vfp_state r7 > + > + add r7, r0, #VCPU_VFP_HOST > + ldr r7, [r7] > + restore_vfp_state r7 > + > + pop {r4-r7} > +#endif > + bx lr > +ENDPROC(kvm_restore_host_vfp_state) > diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S > index 900ef6d..8e25431 100644 > --- a/arch/arm/kvm/interrupts.S > +++ b/arch/arm/kvm/interrupts.S > @@ -116,22 +116,15 @@ ENTRY(__kvm_vcpu_run) > read_cp15_state store_to_vcpu = 0 > write_cp15_state read_from_vcpu = 1 > > - @ If the host kernel has not been configured with VFPv3 support, > - @ then it is safer if we deny guests from using it as well. > -#ifdef CONFIG_VFPv3 > - @ Set FPEXC_EN so the guest doesn't trap floating point instructions > - VFPFMRX r2, FPEXC @ VMRS > - push {r2} > - orr r2, r2, #FPEXC_EN > - VFPFMXR FPEXC, r2 @ VMSR > -#endif > + @ Enable tracing and possibly fp/simd trapping Configure trapping of access to tracing and fp/simd registers > + ldr r4, [vcpu, #VCPU_HCPTR] > + set_hcptr vmentry, #0, r4 if we store something called HCPTR on the VCPU, then that should really be HCPTR, so I don't see why we need a macro and this is not just a write to the HCPTR directly? > > @ Configure Hyp-role > configure_hyp_role vmentry > > @ Trap coprocessor CRx accesses > set_hstr vmentry > - set_hcptr vmentry, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) > set_hdcr vmentry > > @ Write configured ID register into MIDR alias > @@ -170,23 +163,12 @@ __kvm_vcpu_return: > @ Don't trap coprocessor accesses for host kernel > set_hstr vmexit > set_hdcr vmexit > - set_hcptr vmexit, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)), after_vfp_restore > > -#ifdef CONFIG_VFPv3 > - @ Switch VFP/NEON hardware state to the host's > - add r7, vcpu, #VCPU_VFP_GUEST > - store_vfp_state r7 > - add r7, vcpu, #VCPU_VFP_HOST > - ldr r7, [r7] > - restore_vfp_state r7 > + /* Preserve HCPTR across exits */ > + mrc p15, 4, r2, c1, c1, 2 > + str r2, [vcpu, #VCPU_HCPTR] can't you do this in the trap handler so you avoid this on every exit? > > -after_vfp_restore: > - @ Restore FPEXC_EN which we clobbered on entry > - pop {r2} > - VFPFMXR FPEXC, r2 > -#else > -after_vfp_restore: > -#endif > + set_hcptr vmexit, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) again here, I don't think you need a macro, just clear the bits and store the register. > > @ Reset Hyp-role > configure_hyp_role vmexit > diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S > index 51a5950..7701ccd 100644 > --- a/arch/arm/kvm/interrupts_head.S > +++ b/arch/arm/kvm/interrupts_head.S > @@ -593,29 +593,24 @@ ARM_BE8(rev r6, r6 ) > * (hardware reset value is 0). Keep previous value in r2. > * An ISB is emited on vmexit/vmtrap, but executed on vmexit only if > * VFP wasn't already enabled (always executed on vmtrap). > - * If a label is specified with vmexit, it is branched to if VFP wasn't > - * enabled. > */ > -.macro set_hcptr operation, mask, label = none > - mrc p15, 4, r2, c1, c1, 2 > - ldr r3, =\mask > +.macro set_hcptr operation, mask, reg > + mrc p15, 4, r2, c1, c1, 2 > .if \operation == vmentry > - orr r3, r2, r3 @ Trap coproc-accesses defined in mask > + mov r3, \reg @ Trap coproc-accesses defined in mask > .else > - bic r3, r2, r3 @ Don't trap defined coproc-accesses > - .endif > - mcr p15, 4, r3, c1, c1, 2 > - .if \operation != vmentry > - .if \operation == vmexit > - tst r2, #(HCPTR_TCP(10) | HCPTR_TCP(11)) > - beq 1f > - .endif > - isb > - .if \label != none > - b \label > - .endif > + ldr r3, =\mask > + bic r3, r2, r3 @ Don't trap defined coproc-accesses > + .endif > + mcr p15, 4, r3, c1, c1, 2 > + .if \operation != vmentry > + .if \operation == vmexit > + tst r2, #(HCPTR_TCP(10) | HCPTR_TCP(11)) > + beq 1f > + .endif > + isb > 1: > - .endif > + .endif there are white-space issues here, but I think you can rid of this macro entirely now. > .endm > > /* Configures the HDCR (Hyp Debug Configuration Register) on entry/return > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h > index 17e92f0..8dccbd7 100644 > --- a/arch/arm64/include/asm/kvm_emulate.h > +++ b/arch/arm64/include/asm/kvm_emulate.h > @@ -290,4 +290,13 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, > return data; /* Leave LE untouched */ > } > > +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) {} > +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {} > +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) {} > + > +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) > +{ > + return false; > +} > + > #endif /* __ARM64_KVM_EMULATE_H__ */ > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 4562459..e16fd39 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -248,6 +248,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} > 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 kvm_restore_host_vfp_state(struct kvm_vcpu *vcpu) {} > > void kvm_arm_init_debug(void); > void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); > -- > 1.9.1 > Thanks, -Christoffer
On 12/18/2015 5:49 AM, Christoffer Dall wrote: > On Sun, Dec 06, 2015 at 05:07:13PM -0800, Mario Smarduch wrote: >> This patch tracks armv7 fp/simd hardware state with hcptr register. >> On vcpu_load saves host fpexc, enables FP access, and sets trapping >> on fp/simd access. On first fp/simd access trap to handler to save host and >> restore guest context, clear trapping bits to enable vcpu lazy mode. On >> vcpu_put if trap bits are cleared save guest and restore host context and >> always restore host fpexc. >> >> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> >> --- >> arch/arm/include/asm/kvm_emulate.h | 50 ++++++++++++++++++++++++++++++++++++ >> arch/arm/include/asm/kvm_host.h | 1 + >> arch/arm/kvm/Makefile | 2 +- >> arch/arm/kvm/arm.c | 13 ++++++++++ >> arch/arm/kvm/fpsimd_switch.S | 46 +++++++++++++++++++++++++++++++++ >> arch/arm/kvm/interrupts.S | 32 +++++------------------ >> arch/arm/kvm/interrupts_head.S | 33 ++++++++++-------------- >> arch/arm64/include/asm/kvm_emulate.h | 9 +++++++ >> arch/arm64/include/asm/kvm_host.h | 1 + >> 9 files changed, 142 insertions(+), 45 deletions(-) >> create mode 100644 arch/arm/kvm/fpsimd_switch.S >> >> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h >> index a9c80a2..3de11a2 100644 >> --- a/arch/arm/include/asm/kvm_emulate.h >> +++ b/arch/arm/include/asm/kvm_emulate.h >> @@ -243,4 +243,54 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, >> } >> } >> >> +#ifdef CONFIG_VFPv3 >> +/* Called from vcpu_load - save fpexc and enable guest access to fp/simd unit */ > > are you really enabling guest access here or just fiddling with fpexc to > ensure you trap accesses to hyp ? That's the end goal, but it is setting the fp enable bit? Your later comment of combining functions and remove assembler should work. > >> +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) >> +{ >> + u32 fpexc; >> + >> + asm volatile( >> + "mrc p10, 7, %0, cr8, cr0, 0\n" >> + "str %0, [%1]\n" >> + "mov %0, #(1 << 30)\n" >> + "mcr p10, 7, %0, cr8, cr0, 0\n" >> + "isb\n" > > why do you need an ISB here? won't there be an implicit one from the > HVC call later before you need this to take effect? I would think so, but besides B.2.7.3 I can't find other references on visibility of context altering instructions. > >> + : "+r" (fpexc) >> + : "r" (&vcpu->arch.host_fpexc) >> + ); > > this whole bit can be rewritten something like: > > fpexc = fmrx(FPEXC); > vcpu->arch.host_fpexc = fpexc; > fpexc |= FPEXC_EN; > fmxr(FPEXC, fpexc); Didn't know about fmrx/fmxr functions - much better. > >> +} >> + >> +/* Called from vcpu_put - restore host fpexc */ >> +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) >> +{ >> + asm volatile( >> + "mcr p10, 7, %0, cr8, cr0, 0\n" >> + : >> + : "r" (vcpu->arch.host_fpexc) >> + ); > > similarly here Ok. > >> +} >> + >> +/* If trap bits are reset then fp/simd registers are dirty */ >> +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> +{ >> + return !!(~vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11))); > > this looks complicated, how about: > > return !(vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11))); Yeah, I twisted the meaning of bool. > >> +} >> + >> +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) >> +{ >> + vcpu->arch.hcptr |= (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)); >> +} >> +#else >> +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) {} >> +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {} >> +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> +{ >> + return false; >> +} >> +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) >> +{ >> + vcpu->arch.hcptr = HCPTR_TTA; >> +} >> +#endif >> + >> #endif /* __ARM_KVM_EMULATE_H__ */ >> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h >> index 09bb1f2..ecc883a 100644 >> --- a/arch/arm/include/asm/kvm_host.h >> +++ b/arch/arm/include/asm/kvm_host.h >> @@ -227,6 +227,7 @@ int kvm_perf_teardown(void); >> void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); >> >> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr); >> +void kvm_restore_host_vfp_state(struct kvm_vcpu *); >> >> static inline void kvm_arch_hardware_disable(void) {} >> static inline void kvm_arch_hardware_unsetup(void) {} >> diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile >> index c5eef02c..411b3e4 100644 >> --- a/arch/arm/kvm/Makefile >> +++ b/arch/arm/kvm/Makefile >> @@ -19,7 +19,7 @@ kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o $(KVM)/vf >> >> obj-y += kvm-arm.o init.o interrupts.o >> obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o >> -obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o >> +obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o fpsimd_switch.o >> obj-y += $(KVM)/arm/vgic.o >> obj-y += $(KVM)/arm/vgic-v2.o >> obj-y += $(KVM)/arm/vgic-v2-emul.o >> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c >> index dc017ad..1de07ab 100644 >> --- a/arch/arm/kvm/arm.c >> +++ b/arch/arm/kvm/arm.c >> @@ -291,10 +291,23 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) >> vcpu->arch.host_cpu_context = this_cpu_ptr(kvm_host_cpu_state); >> >> kvm_arm_set_running_vcpu(vcpu); >> + >> + /* Save and enable FPEXC before we load guest context */ >> + kvm_enable_vcpu_fpexc(vcpu); > > hmmm, not really sure the 'enable' part of this name is the right choice > when looking at this. kvm_prepare_vcpu_fpexc ? > >> + >> + /* reset hyp cptr register to trap on tracing and vfp/simd access*/ >> + vcpu_reset_cptr(vcpu); > > alternatively you could combine the two functions above into a single > function called something like "vcpu_trap_vfp_enable()" or > "vcpu_load_configure_vfp()" > > (I sort of feel like we have reserved the _reset_ namespace for stuff we > actually do at VCPU reset.) Related to earlier comment I would be in favor of combining and use 'vcpu_trap_vfp_enable()'. > > >> } >> >> void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) >> { >> + /* If the fp/simd registers are dirty save guest, restore host. */ >> + if (kvm_vcpu_vfp_isdirty(vcpu)) >> + kvm_restore_host_vfp_state(vcpu); >> + >> + /* Restore host FPEXC trashed in vcpu_load */ >> + kvm_restore_host_fpexc(vcpu); >> + >> /* >> * The arch-generic KVM code expects the cpu field of a vcpu to be -1 >> * if the vcpu is no longer assigned to a cpu. This is used for the >> diff --git a/arch/arm/kvm/fpsimd_switch.S b/arch/arm/kvm/fpsimd_switch.S >> new file mode 100644 >> index 0000000..d297c54 >> --- /dev/null >> +++ b/arch/arm/kvm/fpsimd_switch.S >> @@ -0,0 +1,46 @@ >> +/* >> + * Copyright (C) 2012 - Virtual Open Systems and Columbia University >> + * Author: Christoffer Dall <c.dall@virtualopensystems.com> > > Not quite, this is new code, so you should just claim copyright and > authorship I believe. Ok didn't know. > >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License, version 2, as >> + * published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + * >> + */ >> +#include <linux/linkage.h> >> +#include <linux/const.h> >> +#include <asm/unified.h> >> +#include <asm/page.h> >> +#include <asm/ptrace.h> >> +#include <asm/asm-offsets.h> >> +#include <asm/kvm_asm.h> >> +#include <asm/kvm_arm.h> >> +#include <asm/vfpmacros.h> >> +#include "interrupts_head.S" >> + >> + .text >> +/** >> + * void kvm_restore_host_vfp_state(struct vcpu *vcpu) - >> + * This function is called from host to save the guest, and restore host >> + * fp/simd hardware context. It's placed outside of hyp start/end region. >> + */ >> +ENTRY(kvm_restore_host_vfp_state) >> +#ifdef CONFIG_VFPv3 >> + push {r4-r7} >> + >> + add r7, r0, #VCPU_VFP_GUEST >> + store_vfp_state r7 >> + >> + add r7, r0, #VCPU_VFP_HOST >> + ldr r7, [r7] >> + restore_vfp_state r7 >> + >> + pop {r4-r7} >> +#endif >> + bx lr >> +ENDPROC(kvm_restore_host_vfp_state) >> diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S >> index 900ef6d..8e25431 100644 >> --- a/arch/arm/kvm/interrupts.S >> +++ b/arch/arm/kvm/interrupts.S >> @@ -116,22 +116,15 @@ ENTRY(__kvm_vcpu_run) >> read_cp15_state store_to_vcpu = 0 >> write_cp15_state read_from_vcpu = 1 >> >> - @ If the host kernel has not been configured with VFPv3 support, >> - @ then it is safer if we deny guests from using it as well. >> -#ifdef CONFIG_VFPv3 >> - @ Set FPEXC_EN so the guest doesn't trap floating point instructions >> - VFPFMRX r2, FPEXC @ VMRS >> - push {r2} >> - orr r2, r2, #FPEXC_EN >> - VFPFMXR FPEXC, r2 @ VMSR >> -#endif >> + @ Enable tracing and possibly fp/simd trapping > > Configure trapping of access to tracing and fp/simd registers ok. > >> + ldr r4, [vcpu, #VCPU_HCPTR] >> + set_hcptr vmentry, #0, r4 > > if we store something called HCPTR on the VCPU, then that should really > be HCPTR, so I don't see why we need a macro and this is not just a > write to the HCPTR directly? The macro handled some corner cases, but it's getting messy. I'll remove it. > >> >> @ Configure Hyp-role >> configure_hyp_role vmentry >> >> @ Trap coprocessor CRx accesses >> set_hstr vmentry >> - set_hcptr vmentry, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) >> set_hdcr vmentry >> >> @ Write configured ID register into MIDR alias >> @@ -170,23 +163,12 @@ __kvm_vcpu_return: >> @ Don't trap coprocessor accesses for host kernel >> set_hstr vmexit >> set_hdcr vmexit >> - set_hcptr vmexit, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)), after_vfp_restore >> >> -#ifdef CONFIG_VFPv3 >> - @ Switch VFP/NEON hardware state to the host's >> - add r7, vcpu, #VCPU_VFP_GUEST >> - store_vfp_state r7 >> - add r7, vcpu, #VCPU_VFP_HOST >> - ldr r7, [r7] >> - restore_vfp_state r7 >> + /* Preserve HCPTR across exits */ >> + mrc p15, 4, r2, c1, c1, 2 >> + str r2, [vcpu, #VCPU_HCPTR] > > can't you do this in the trap handler so you avoid this on every exit Ah right you could, updated register is retained until next vcpu_load. > >> >> -after_vfp_restore: >> - @ Restore FPEXC_EN which we clobbered on entry >> - pop {r2} >> - VFPFMXR FPEXC, r2 >> -#else >> -after_vfp_restore: >> -#endif >> + set_hcptr vmexit, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) > > again here, I don't think you need a macro, just clear the bits and > store the register. > >> >> @ Reset Hyp-role >> configure_hyp_role vmexit >> diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S >> index 51a5950..7701ccd 100644 >> --- a/arch/arm/kvm/interrupts_head.S >> +++ b/arch/arm/kvm/interrupts_head.S >> @@ -593,29 +593,24 @@ ARM_BE8(rev r6, r6 ) >> * (hardware reset value is 0). Keep previous value in r2. >> * An ISB is emited on vmexit/vmtrap, but executed on vmexit only if >> * VFP wasn't already enabled (always executed on vmtrap). >> - * If a label is specified with vmexit, it is branched to if VFP wasn't >> - * enabled. >> */ >> -.macro set_hcptr operation, mask, label = none >> - mrc p15, 4, r2, c1, c1, 2 >> - ldr r3, =\mask >> +.macro set_hcptr operation, mask, reg >> + mrc p15, 4, r2, c1, c1, 2 >> .if \operation == vmentry >> - orr r3, r2, r3 @ Trap coproc-accesses defined in mask >> + mov r3, \reg @ Trap coproc-accesses defined in mask >> .else >> - bic r3, r2, r3 @ Don't trap defined coproc-accesses >> - .endif >> - mcr p15, 4, r3, c1, c1, 2 >> - .if \operation != vmentry >> - .if \operation == vmexit >> - tst r2, #(HCPTR_TCP(10) | HCPTR_TCP(11)) >> - beq 1f >> - .endif >> - isb >> - .if \label != none >> - b \label >> - .endif >> + ldr r3, =\mask >> + bic r3, r2, r3 @ Don't trap defined coproc-accesses >> + .endif >> + mcr p15, 4, r3, c1, c1, 2 >> + .if \operation != vmentry >> + .if \operation == vmexit >> + tst r2, #(HCPTR_TCP(10) | HCPTR_TCP(11)) >> + beq 1f >> + .endif >> + isb >> 1: >> - .endif >> + .endif > > there are white-space issues here, but I think you can rid of this macro > entirely now. > >> .endm >> >> /* Configures the HDCR (Hyp Debug Configuration Register) on entry/return >> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h >> index 17e92f0..8dccbd7 100644 >> --- a/arch/arm64/include/asm/kvm_emulate.h >> +++ b/arch/arm64/include/asm/kvm_emulate.h >> @@ -290,4 +290,13 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, >> return data; /* Leave LE untouched */ >> } >> >> +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) {} >> +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {} >> +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) {} >> + >> +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) >> +{ >> + return false; >> +} >> + >> #endif /* __ARM64_KVM_EMULATE_H__ */ >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h >> index 4562459..e16fd39 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -248,6 +248,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} >> 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 kvm_restore_host_vfp_state(struct kvm_vcpu *vcpu) {} >> >> void kvm_arm_init_debug(void); >> void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); >> -- >> 1.9.1 >> > > Thanks, > -Christoffer >
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h index a9c80a2..3de11a2 100644 --- a/arch/arm/include/asm/kvm_emulate.h +++ b/arch/arm/include/asm/kvm_emulate.h @@ -243,4 +243,54 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, } } +#ifdef CONFIG_VFPv3 +/* Called from vcpu_load - save fpexc and enable guest access to fp/simd unit */ +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) +{ + u32 fpexc; + + asm volatile( + "mrc p10, 7, %0, cr8, cr0, 0\n" + "str %0, [%1]\n" + "mov %0, #(1 << 30)\n" + "mcr p10, 7, %0, cr8, cr0, 0\n" + "isb\n" + : "+r" (fpexc) + : "r" (&vcpu->arch.host_fpexc) + ); +} + +/* Called from vcpu_put - restore host fpexc */ +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) +{ + asm volatile( + "mcr p10, 7, %0, cr8, cr0, 0\n" + : + : "r" (vcpu->arch.host_fpexc) + ); +} + +/* If trap bits are reset then fp/simd registers are dirty */ +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) +{ + return !!(~vcpu->arch.hcptr & (HCPTR_TCP(10) | HCPTR_TCP(11))); +} + +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) +{ + vcpu->arch.hcptr |= (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)); +} +#else +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) {} +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {} +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) +{ + return false; +} +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) +{ + vcpu->arch.hcptr = HCPTR_TTA; +} +#endif + #endif /* __ARM_KVM_EMULATE_H__ */ diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 09bb1f2..ecc883a 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -227,6 +227,7 @@ int kvm_perf_teardown(void); void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr); +void kvm_restore_host_vfp_state(struct kvm_vcpu *); static inline void kvm_arch_hardware_disable(void) {} static inline void kvm_arch_hardware_unsetup(void) {} diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile index c5eef02c..411b3e4 100644 --- a/arch/arm/kvm/Makefile +++ b/arch/arm/kvm/Makefile @@ -19,7 +19,7 @@ kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o $(KVM)/vf obj-y += kvm-arm.o init.o interrupts.o obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o -obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o +obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o fpsimd_switch.o obj-y += $(KVM)/arm/vgic.o obj-y += $(KVM)/arm/vgic-v2.o obj-y += $(KVM)/arm/vgic-v2-emul.o diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index dc017ad..1de07ab 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -291,10 +291,23 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) vcpu->arch.host_cpu_context = this_cpu_ptr(kvm_host_cpu_state); kvm_arm_set_running_vcpu(vcpu); + + /* Save and enable FPEXC before we load guest context */ + kvm_enable_vcpu_fpexc(vcpu); + + /* reset hyp cptr register to trap on tracing and vfp/simd access*/ + vcpu_reset_cptr(vcpu); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { + /* If the fp/simd registers are dirty save guest, restore host. */ + if (kvm_vcpu_vfp_isdirty(vcpu)) + kvm_restore_host_vfp_state(vcpu); + + /* Restore host FPEXC trashed in vcpu_load */ + kvm_restore_host_fpexc(vcpu); + /* * The arch-generic KVM code expects the cpu field of a vcpu to be -1 * if the vcpu is no longer assigned to a cpu. This is used for the diff --git a/arch/arm/kvm/fpsimd_switch.S b/arch/arm/kvm/fpsimd_switch.S new file mode 100644 index 0000000..d297c54 --- /dev/null +++ b/arch/arm/kvm/fpsimd_switch.S @@ -0,0 +1,46 @@ +/* + * Copyright (C) 2012 - Virtual Open Systems and Columbia University + * Author: Christoffer Dall <c.dall@virtualopensystems.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, version 2, as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ +#include <linux/linkage.h> +#include <linux/const.h> +#include <asm/unified.h> +#include <asm/page.h> +#include <asm/ptrace.h> +#include <asm/asm-offsets.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_arm.h> +#include <asm/vfpmacros.h> +#include "interrupts_head.S" + + .text +/** + * void kvm_restore_host_vfp_state(struct vcpu *vcpu) - + * This function is called from host to save the guest, and restore host + * fp/simd hardware context. It's placed outside of hyp start/end region. + */ +ENTRY(kvm_restore_host_vfp_state) +#ifdef CONFIG_VFPv3 + push {r4-r7} + + add r7, r0, #VCPU_VFP_GUEST + store_vfp_state r7 + + add r7, r0, #VCPU_VFP_HOST + ldr r7, [r7] + restore_vfp_state r7 + + pop {r4-r7} +#endif + bx lr +ENDPROC(kvm_restore_host_vfp_state) diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S index 900ef6d..8e25431 100644 --- a/arch/arm/kvm/interrupts.S +++ b/arch/arm/kvm/interrupts.S @@ -116,22 +116,15 @@ ENTRY(__kvm_vcpu_run) read_cp15_state store_to_vcpu = 0 write_cp15_state read_from_vcpu = 1 - @ If the host kernel has not been configured with VFPv3 support, - @ then it is safer if we deny guests from using it as well. -#ifdef CONFIG_VFPv3 - @ Set FPEXC_EN so the guest doesn't trap floating point instructions - VFPFMRX r2, FPEXC @ VMRS - push {r2} - orr r2, r2, #FPEXC_EN - VFPFMXR FPEXC, r2 @ VMSR -#endif + @ Enable tracing and possibly fp/simd trapping + ldr r4, [vcpu, #VCPU_HCPTR] + set_hcptr vmentry, #0, r4 @ Configure Hyp-role configure_hyp_role vmentry @ Trap coprocessor CRx accesses set_hstr vmentry - set_hcptr vmentry, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) set_hdcr vmentry @ Write configured ID register into MIDR alias @@ -170,23 +163,12 @@ __kvm_vcpu_return: @ Don't trap coprocessor accesses for host kernel set_hstr vmexit set_hdcr vmexit - set_hcptr vmexit, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)), after_vfp_restore -#ifdef CONFIG_VFPv3 - @ Switch VFP/NEON hardware state to the host's - add r7, vcpu, #VCPU_VFP_GUEST - store_vfp_state r7 - add r7, vcpu, #VCPU_VFP_HOST - ldr r7, [r7] - restore_vfp_state r7 + /* Preserve HCPTR across exits */ + mrc p15, 4, r2, c1, c1, 2 + str r2, [vcpu, #VCPU_HCPTR] -after_vfp_restore: - @ Restore FPEXC_EN which we clobbered on entry - pop {r2} - VFPFMXR FPEXC, r2 -#else -after_vfp_restore: -#endif + set_hcptr vmexit, (HCPTR_TTA | HCPTR_TCP(10) | HCPTR_TCP(11)) @ Reset Hyp-role configure_hyp_role vmexit diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S index 51a5950..7701ccd 100644 --- a/arch/arm/kvm/interrupts_head.S +++ b/arch/arm/kvm/interrupts_head.S @@ -593,29 +593,24 @@ ARM_BE8(rev r6, r6 ) * (hardware reset value is 0). Keep previous value in r2. * An ISB is emited on vmexit/vmtrap, but executed on vmexit only if * VFP wasn't already enabled (always executed on vmtrap). - * If a label is specified with vmexit, it is branched to if VFP wasn't - * enabled. */ -.macro set_hcptr operation, mask, label = none - mrc p15, 4, r2, c1, c1, 2 - ldr r3, =\mask +.macro set_hcptr operation, mask, reg + mrc p15, 4, r2, c1, c1, 2 .if \operation == vmentry - orr r3, r2, r3 @ Trap coproc-accesses defined in mask + mov r3, \reg @ Trap coproc-accesses defined in mask .else - bic r3, r2, r3 @ Don't trap defined coproc-accesses - .endif - mcr p15, 4, r3, c1, c1, 2 - .if \operation != vmentry - .if \operation == vmexit - tst r2, #(HCPTR_TCP(10) | HCPTR_TCP(11)) - beq 1f - .endif - isb - .if \label != none - b \label - .endif + ldr r3, =\mask + bic r3, r2, r3 @ Don't trap defined coproc-accesses + .endif + mcr p15, 4, r3, c1, c1, 2 + .if \operation != vmentry + .if \operation == vmexit + tst r2, #(HCPTR_TCP(10) | HCPTR_TCP(11)) + beq 1f + .endif + isb 1: - .endif + .endif .endm /* Configures the HDCR (Hyp Debug Configuration Register) on entry/return diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 17e92f0..8dccbd7 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -290,4 +290,13 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, return data; /* Leave LE untouched */ } +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) {} +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {} +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) {} + +static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu) +{ + return false; +} + #endif /* __ARM64_KVM_EMULATE_H__ */ diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 4562459..e16fd39 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -248,6 +248,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} 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 kvm_restore_host_vfp_state(struct kvm_vcpu *vcpu) {} void kvm_arm_init_debug(void); void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
This patch tracks armv7 fp/simd hardware state with hcptr register. On vcpu_load saves host fpexc, enables FP access, and sets trapping on fp/simd access. On first fp/simd access trap to handler to save host and restore guest context, clear trapping bits to enable vcpu lazy mode. On vcpu_put if trap bits are cleared save guest and restore host context and always restore host fpexc. Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> --- arch/arm/include/asm/kvm_emulate.h | 50 ++++++++++++++++++++++++++++++++++++ arch/arm/include/asm/kvm_host.h | 1 + arch/arm/kvm/Makefile | 2 +- arch/arm/kvm/arm.c | 13 ++++++++++ arch/arm/kvm/fpsimd_switch.S | 46 +++++++++++++++++++++++++++++++++ arch/arm/kvm/interrupts.S | 32 +++++------------------ arch/arm/kvm/interrupts_head.S | 33 ++++++++++-------------- arch/arm64/include/asm/kvm_emulate.h | 9 +++++++ arch/arm64/include/asm/kvm_host.h | 1 + 9 files changed, 142 insertions(+), 45 deletions(-) create mode 100644 arch/arm/kvm/fpsimd_switch.S