diff options
| -rw-r--r-- | arch/arm/include/asm/kvm_host.h | 8 | ||||
| -rw-r--r-- | arch/arm64/include/asm/fpsimd.h | 6 | ||||
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 21 | ||||
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 19 | ||||
| -rw-r--r-- | arch/arm64/kvm/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/Makefile | 2 | ||||
| -rw-r--r-- | arch/arm64/kvm/fpsimd.c | 111 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 51 | ||||
| -rw-r--r-- | virt/kvm/arm/arm.c | 4 |
9 files changed, 192 insertions, 31 deletions
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index c7c28c8..ac870b2 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -303,6 +303,14 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu, int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); +/* + * VFP/NEON switching is all done by the hyp switch code, so no need to + * coordinate with host context handling for this state: + */ +static inline void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) {} +static inline void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) {} +static inline void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) {} + /* All host FP/SIMD state is restored on guest exit, so nothing to save: */ static inline void kvm_fpsimd_flush_cpu_state(void) {} diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index aa7162a..3e00f70 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -41,6 +41,8 @@ struct task_struct; extern void fpsimd_save_state(struct user_fpsimd_state *state); extern void fpsimd_load_state(struct user_fpsimd_state *state); +extern void fpsimd_save(void); + extern void fpsimd_thread_switch(struct task_struct *next); extern void fpsimd_flush_thread(void); @@ -49,7 +51,11 @@ extern void fpsimd_preserve_current_state(void); extern void fpsimd_restore_current_state(void); extern void fpsimd_update_current_state(struct user_fpsimd_state const *state); +extern void fpsimd_bind_task_to_cpu(void); +extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state); + extern void fpsimd_flush_task_state(struct task_struct *target); +extern void fpsimd_flush_cpu_state(void); extern void sve_flush_cpu_state(void); /* Maximum VL that SVE VL-agnostic software can transparently support */ diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 146c167..b3fe730 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -30,6 +30,7 @@ #include <asm/kvm.h> #include <asm/kvm_asm.h> #include <asm/kvm_mmio.h> +#include <asm/thread_info.h> #define __KVM_HAVE_ARCH_INTC_INITIALIZED @@ -238,6 +239,10 @@ struct kvm_vcpu_arch { /* Pointer to host CPU context */ kvm_cpu_context_t *host_cpu_context; + + struct thread_info *host_thread_info; /* hyp VA */ + struct user_fpsimd_state *host_fpsimd_state; /* hyp VA */ + struct { /* {Break,watch}point registers */ struct kvm_guest_debug_arch regs; @@ -295,6 +300,9 @@ struct kvm_vcpu_arch { /* vcpu_arch flags field values: */ #define KVM_ARM64_DEBUG_DIRTY (1 << 0) +#define KVM_ARM64_FP_ENABLED (1 << 1) /* guest FP regs loaded */ +#define KVM_ARM64_FP_HOST (1 << 2) /* host FP regs loaded */ +#define KVM_ARM64_HOST_SVE_IN_USE (1 << 3) /* backup for host TIF_SVE */ #define vcpu_gp_regs(v) (&(v)->arch.ctxt.gp_regs) @@ -423,6 +431,19 @@ static inline void __cpu_init_stage2(void) "PARange is %d bits, unsupported configuration!", parange); } +/* Guest/host FPSIMD coordination helpers */ +int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu); +void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu); +void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu); +void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu); + +#ifdef CONFIG_KVM /* Avoid conflicts with core headers if CONFIG_KVM=n */ +static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) +{ + return kvm_arch_vcpu_run_map_fp(vcpu); +} +#endif + /* * All host FP/SIMD state is restored on guest exit, so nothing needs * doing here except in the SVE case: diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index d5f659f..794dd99 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -265,10 +265,10 @@ static void task_fpsimd_load(void) * * Softirqs (and preemption) must be disabled. */ -static void fpsimd_save(void) +void fpsimd_save(void) { struct user_fpsimd_state *st = __this_cpu_read(fpsimd_last_state.st); - /* set by fpsimd_bind_task_to_cpu() */ + /* set by fpsimd_bind_task_to_cpu() or fpsimd_bind_state_to_cpu() */ WARN_ON(!in_softirq() && !irqs_disabled()); @@ -986,7 +986,7 @@ void fpsimd_signal_preserve_current_state(void) * Associate current's FPSIMD context with this cpu * Preemption must be disabled when calling this function. */ -static void fpsimd_bind_task_to_cpu(void) +void fpsimd_bind_task_to_cpu(void) { struct fpsimd_last_state_struct *last = this_cpu_ptr(&fpsimd_last_state); @@ -1006,6 +1006,17 @@ static void fpsimd_bind_task_to_cpu(void) } } +void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st) +{ + struct fpsimd_last_state_struct *last = + this_cpu_ptr(&fpsimd_last_state); + + WARN_ON(!in_softirq() && !irqs_disabled()); + + last->st = st; + last->sve_in_use = false; +} + /* * Load the userland FPSIMD state of 'current' from memory, but only if the * FPSIMD state already held in the registers is /not/ the most recent FPSIMD @@ -1058,7 +1069,7 @@ void fpsimd_flush_task_state(struct task_struct *t) t->thread.fpsimd_cpu = NR_CPUS; } -static inline void fpsimd_flush_cpu_state(void) +void fpsimd_flush_cpu_state(void) { __this_cpu_write(fpsimd_last_state.st, NULL); set_thread_flag(TIF_FOREIGN_FPSTATE); diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index a2e3a5a..47b23bf 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -39,6 +39,7 @@ config KVM select HAVE_KVM_IRQ_ROUTING select IRQ_BYPASS_MANAGER select HAVE_KVM_IRQ_BYPASS + select HAVE_KVM_VCPU_RUN_PID_CHANGE ---help--- Support hosting virtualized guest machines. We don't support KVM with 16K page tables yet, due to the multiple diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 93afff9..0f2a135 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -19,7 +19,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/psci.o $(KVM)/arm/perf.o kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o va_layout.o kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o -kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o +kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o fpsimd.o kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/aarch32.o kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic.o diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c new file mode 100644 index 0000000..365933a --- /dev/null +++ b/arch/arm64/kvm/fpsimd.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * arch/arm64/kvm/fpsimd.c: Guest/host FPSIMD context coordination helpers + * + * Copyright 2018 Arm Limited + * Author: Dave Martin <Dave.Martin@arm.com> + */ +#include <linux/bottom_half.h> +#include <linux/sched.h> +#include <linux/thread_info.h> +#include <linux/kvm_host.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_host.h> +#include <asm/kvm_mmu.h> + +/* + * Called on entry to KVM_RUN unless this vcpu previously ran at least + * once and the most recent prior KVM_RUN for this vcpu was called from + * the same task as current (highly likely). + * + * This is guaranteed to execute before kvm_arch_vcpu_load_fp(vcpu), + * such that on entering hyp the relevant parts of current are already + * mapped. + */ +int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) +{ + int ret; + + struct thread_info *ti = ¤t->thread_info; + struct user_fpsimd_state *fpsimd = ¤t->thread.uw.fpsimd_state; + + /* + * Make sure the host task thread flags and fpsimd state are + * visible to hyp: + */ + ret = create_hyp_mappings(ti, ti + 1, PAGE_HYP); + if (ret) + goto error; + + ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP); + if (ret) + goto error; + + vcpu->arch.host_thread_info = kern_hyp_va(ti); + vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); +error: + return ret; +} + +/* + * Prepare vcpu for saving the host's FPSIMD state and loading the guest's. + * The actual loading is done by the FPSIMD access trap taken to hyp. + * + * Here, we just set the correct metadata to indicate that the FPSIMD + * state in the cpu regs (if any) belongs to current on the host. + * + * TIF_SVE is backed up here, since it may get clobbered with guest state. + * This flag is restored by kvm_arch_vcpu_put_fp(vcpu). + */ +void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) +{ + BUG_ON(system_supports_sve()); + BUG_ON(!current->mm); + + vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | KVM_ARM64_HOST_SVE_IN_USE); + vcpu->arch.flags |= KVM_ARM64_FP_HOST; + if (test_thread_flag(TIF_SVE)) + vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE; +} + +/* + * If the guest FPSIMD state was loaded, update the host's context + * tracking data mark the CPU FPSIMD regs as dirty and belonging to vcpu + * so that they will be written back if the kernel clobbers them due to + * kernel-mode NEON before re-entry into the guest. + */ +void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) +{ + WARN_ON_ONCE(!irqs_disabled()); + + if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) { + fpsimd_bind_state_to_cpu(&vcpu->arch.ctxt.gp_regs.fp_regs); + clear_thread_flag(TIF_FOREIGN_FPSTATE); + clear_thread_flag(TIF_SVE); + } +} + +/* + * Write back the vcpu FPSIMD regs if they are dirty, and invalidate the + * cpu FPSIMD regs so that they can't be spuriously reused if this vcpu + * disappears and another task or vcpu appears that recycles the same + * struct fpsimd_state. + */ +void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) +{ + local_bh_disable(); + + update_thread_flag(TIF_SVE, + vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE); + + if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) { + /* Clean guest FP state to memory and invalidate cpu view */ + fpsimd_save(); + fpsimd_flush_cpu_state(); + } else if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { + /* Ensure user trap controls are correctly restored */ + fpsimd_bind_task_to_cpu(); + } + + local_bh_enable(); +} diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index c0796c4..118f300 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -23,19 +23,21 @@ #include <asm/kvm_asm.h> #include <asm/kvm_emulate.h> +#include <asm/kvm_host.h> #include <asm/kvm_hyp.h> #include <asm/kvm_mmu.h> #include <asm/fpsimd.h> #include <asm/debug-monitors.h> +#include <asm/thread_info.h> -static bool __hyp_text __fpsimd_enabled_nvhe(void) +/* Check whether the FP regs were dirtied while in the host-side run loop: */ +static bool __hyp_text update_fp_enabled(struct kvm_vcpu *vcpu) { - return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP); -} + if (vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE) + vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | + KVM_ARM64_FP_HOST); -static bool fpsimd_enabled_vhe(void) -{ - return !!(read_sysreg(cpacr_el1) & CPACR_EL1_FPEN); + return !!(vcpu->arch.flags & KVM_ARM64_FP_ENABLED); } /* Save the 32-bit only FPSIMD system register state */ @@ -92,7 +94,10 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu) val = read_sysreg(cpacr_el1); val |= CPACR_EL1_TTA; - val &= ~(CPACR_EL1_FPEN | CPACR_EL1_ZEN); + val &= ~CPACR_EL1_ZEN; + if (!update_fp_enabled(vcpu)) + val &= ~CPACR_EL1_FPEN; + write_sysreg(val, cpacr_el1); write_sysreg(kvm_get_hyp_vector(), vbar_el1); @@ -105,7 +110,10 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) __activate_traps_common(vcpu); val = CPTR_EL2_DEFAULT; - val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ; + val |= CPTR_EL2_TTA | CPTR_EL2_TZ; + if (!update_fp_enabled(vcpu)) + val |= CPTR_EL2_TFP; + write_sysreg(val, cptr_el2); } @@ -321,8 +329,6 @@ static bool __hyp_text __skip_instr(struct kvm_vcpu *vcpu) void __hyp_text __hyp_switch_fpsimd(u64 esr __always_unused, struct kvm_vcpu *vcpu) { - kvm_cpu_context_t *host_ctxt; - if (has_vhe()) write_sysreg(read_sysreg(cpacr_el1) | CPACR_EL1_FPEN, cpacr_el1); @@ -332,14 +338,19 @@ void __hyp_text __hyp_switch_fpsimd(u64 esr __always_unused, isb(); - host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); - __fpsimd_save_state(&host_ctxt->gp_regs.fp_regs); + if (vcpu->arch.flags & KVM_ARM64_FP_HOST) { + __fpsimd_save_state(vcpu->arch.host_fpsimd_state); + vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; + } + __fpsimd_restore_state(&vcpu->arch.ctxt.gp_regs.fp_regs); /* Skip restoring fpexc32 for AArch64 guests */ if (!(read_sysreg(hcr_el2) & HCR_RW)) write_sysreg(vcpu->arch.ctxt.sys_regs[FPEXC32_EL2], fpexc32_el2); + + vcpu->arch.flags |= KVM_ARM64_FP_ENABLED; } /* @@ -418,7 +429,6 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) { struct kvm_cpu_context *host_ctxt; struct kvm_cpu_context *guest_ctxt; - bool fp_enabled; u64 exit_code; host_ctxt = vcpu->arch.host_cpu_context; @@ -440,19 +450,14 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) /* And we're baaack! */ } while (fixup_guest_exit(vcpu, &exit_code)); - fp_enabled = fpsimd_enabled_vhe(); - sysreg_save_guest_state_vhe(guest_ctxt); __deactivate_traps(vcpu); sysreg_restore_host_state_vhe(host_ctxt); - if (fp_enabled) { - __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs); - __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs); + if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) __fpsimd_save_fpexc32(vcpu); - } __debug_switch_to_host(vcpu); @@ -464,7 +469,6 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) { struct kvm_cpu_context *host_ctxt; struct kvm_cpu_context *guest_ctxt; - bool fp_enabled; u64 exit_code; vcpu = kern_hyp_va(vcpu); @@ -496,8 +500,6 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) /* And we're baaack! */ } while (fixup_guest_exit(vcpu, &exit_code)); - fp_enabled = __fpsimd_enabled_nvhe(); - __sysreg_save_state_nvhe(guest_ctxt); __sysreg32_save_state(vcpu); __timer_disable_traps(vcpu); @@ -508,11 +510,8 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) __sysreg_restore_state_nvhe(host_ctxt); - if (fp_enabled) { - __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs); - __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs); + if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) __fpsimd_save_fpexc32(vcpu); - } /* * This must come after restoring the host sysregs, since a non-VHE diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index a4c1b76..bee226c 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -363,10 +363,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) kvm_vgic_load(vcpu); kvm_timer_vcpu_load(vcpu); kvm_vcpu_load_sysregs(vcpu); + kvm_arch_vcpu_load_fp(vcpu); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { + kvm_arch_vcpu_put_fp(vcpu); kvm_vcpu_put_sysregs(vcpu); kvm_timer_vcpu_put(vcpu); kvm_vgic_put(vcpu); @@ -778,6 +780,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) if (static_branch_unlikely(&userspace_irqchip_in_use)) kvm_timer_sync_hwstate(vcpu); + kvm_arch_vcpu_ctxsync_fp(vcpu); + /* * We may have taken a host interrupt in HYP mode (ie * while executing the guest). This interrupt is still |
