[-next,v13,17/19] riscv: KVM: Add vector lazy save/restore support

Message ID	20230125142056.18356-18-andy.chiu@sifive.com
State	Superseded
Headers	show Return-Path: <kvm-riscv-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org> From: Andy Chiu <andy.chiu@sifive.com> To: linux-riscv@lists.infradead.org, palmer@dabbelt.com, anup@brainfault.org, atishp@atishpatra.org, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org Cc: vineetg@rivosinc.com, greentime.hu@sifive.com, guoren@linux.alibaba.com, Vincent Chen <vincent.chen@sifive.com>, Andy Chiu <andy.chiu@sifive.com>, Paul Walmsley <paul.walmsley@sifive.com>, Albert Ou <aou@eecs.berkeley.edu> Subject: [PATCH -next v13 17/19] riscv: KVM: Add vector lazy save/restore support Date: Wed, 25 Jan 2023 14:20:54 +0000 Message-Id: <20230125142056.18356-18-andy.chiu@sifive.com> In-Reply-To: <20230125142056.18356-1-andy.chiu@sifive.com> References: <20230125142056.18356-1-andy.chiu@sifive.com> preview: From: Vincent Chen <vincent.chen@sifive.com> This patch adds vector context save/restore for guest VCPUs. To reduce the impact on KVM performance, the implementation imitates the FP context switch mechanism to lazily store and restore the vector [...] Content analysis details: (-0.2 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:633 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kvm-riscv" <kvm-riscv-bounces@lists.infradead.org> Errors-To: kvm-riscv-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org
Series	riscv: Add vector ISA support \| expand [-next,v13,00/19] riscv: Add vector ISA support [-next,v13,01/19] riscv: Rename __switch_to_aux -> fpu [-next,v13,02/19] riscv: Extending cpufeature.c to detect V-extension [-next,v13,03/19] riscv: Add new csr defines related to vector extension [-next,v13,04/19] riscv: Clear vector regfile on bootup [-next,v13,05/19] riscv: Disable Vector Instructions for kernel itself [-next,v13,06/19] riscv: Introduce Vector enable/disable helpers [-next,v13,07/19] riscv: Introduce riscv_vsize to record size of Vector context [-next,v13,08/19] riscv: Introduce struct/helpers to save/restore per-task Vector state [-next,v13,09/19] riscv: Add task switch support for vector [-next,v13,10/19] riscv: Allocate user's vector context in the first-use trap [-next,v13,11/19] riscv: Add ptrace vector support [-next,v13,12/19] riscv: signal: check fp-reserved words unconditionally [-next,v13,13/19] riscv: signal: Add sigcontext save/restore for vector [-next,v13,14/19] riscv: signal: Report signal frame size to userspace via auxv [-next,v13,15/19] riscv: Fix a kernel panic issue if $s2 is set to a specific value before entering… [-next,v13,16/19] riscv: Add V extension to KVM ISA [-next,v13,17/19] riscv: KVM: Add vector lazy save/restore support [-next,v13,18/19] riscv: kvm: redirect illegal instruction traps to guests [-next,v13,19/19] riscv: Enable Vector code to be built

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 93f43a3e7886..f96c3f8d9586 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -14,6 +14,7 @@ #include <linux/kvm_types.h> #include <linux/spinlock.h> #include <asm/hwcap.h> +#include <asm/ptrace.h> #include <asm/kvm_vcpu_fp.h> #include <asm/kvm_vcpu_insn.h> #include <asm/kvm_vcpu_sbi.h> @@ -140,6 +141,7 @@ struct kvm_cpu_context { unsigned long sstatus; unsigned long hstatus; union __riscv_fp_state fp; + struct __riscv_v_state vector; }; struct kvm_vcpu_csr { diff --git a/arch/riscv/include/asm/kvm_vcpu_vector.h b/arch/riscv/include/asm/kvm_vcpu_vector.h new file mode 100644 index 000000000000..b0cc6ed25642 --- /dev/null +++ b/arch/riscv/include/asm/kvm_vcpu_vector.h @@ -0,0 +1,77 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2021 Western Digital Corporation or its affiliates. + * Copyright (C) 2022 SiFive + * + * Authors: + * Atish Patra <atish.patra@wdc.com> + * Anup Patel <anup.patel@wdc.com> + * Vincent Chen <vincent.chen@sifive.com> + * Greentime Hu <greentime.hu@sifive.com> + */ + +#ifndef __KVM_VCPU_RISCV_VECTOR_H +#define __KVM_VCPU_RISCV_VECTOR_H + +#include <linux/types.h> + +#ifdef CONFIG_RISCV_ISA_V +#include <asm/vector.h> +#include <asm/kvm_host.h> + +static __always_inline void __kvm_riscv_vector_save(struct kvm_cpu_context *context) +{ + __vstate_save(&context->vector, context->vector.datap); +} + +static __always_inline void __kvm_riscv_vector_restore(struct kvm_cpu_context *context) +{ + __vstate_restore(&context->vector, context->vector.datap); +} + +void kvm_riscv_vcpu_vector_reset(struct kvm_vcpu *vcpu); +void kvm_riscv_vcpu_guest_vector_save(struct kvm_cpu_context *cntx, + unsigned long *isa); +void kvm_riscv_vcpu_guest_vector_restore(struct kvm_cpu_context *cntx, + unsigned long *isa); +void kvm_riscv_vcpu_host_vector_save(struct kvm_cpu_context *cntx); +void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cntx); +void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu); +#else + +struct kvm_cpu_context; + +static inline void kvm_riscv_vcpu_vector_reset(struct kvm_vcpu *vcpu) +{ +} + +static inline void kvm_riscv_vcpu_guest_vector_save(struct kvm_cpu_context *cntx, + unsigned long *isa) +{ +} + +static inline void kvm_riscv_vcpu_guest_vector_restore(struct kvm_cpu_context *cntx, + unsigned long *isa) +{ +} + +static inline void kvm_riscv_vcpu_host_vector_save(struct kvm_cpu_context *cntx) +{ +} + +static inline void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cntx) +{ +} + +static inline void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu) +{ +} +#endif + +int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg, + unsigned long rtype); +int kvm_riscv_vcpu_set_reg_vector(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg, + unsigned long rtype); +#endif diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index e7c9183ad4af..f82fc17fef27 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -153,6 +153,13 @@ enum KVM_RISCV_ISA_EXT_ID { /* ISA Extension registers are mapped as type 7 */ #define KVM_REG_RISCV_ISA_EXT (0x07 << KVM_REG_RISCV_TYPE_SHIFT) +/* V extension registers are mapped as type 8 */ +#define KVM_REG_RISCV_VECTOR (0x08 << KVM_REG_RISCV_TYPE_SHIFT) +#define KVM_REG_RISCV_VECTOR_CSR_REG(name) \ + (offsetof(struct __riscv_v_state, name) / sizeof(unsigned long)) +#define KVM_REG_RISCV_VECTOR_REG(n) \ + ((n) + sizeof(struct __riscv_v_state) / sizeof(unsigned long)) + #endif #endif /* __LINUX_KVM_RISCV_H */ diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile index 019df9208bdd..b26bc605a267 100644 --- a/arch/riscv/kvm/Makefile +++ b/arch/riscv/kvm/Makefile @@ -17,6 +17,7 @@ kvm-y += mmu.o kvm-y += vcpu.o kvm-y += vcpu_exit.o kvm-y += vcpu_fp.o +kvm-y += vcpu_vector.o kvm-y += vcpu_insn.o kvm-y += vcpu_switch.o kvm-y += vcpu_sbi.o diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index b060d26ab783..0bbf67bd76f4 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -22,6 +22,8 @@ #include <asm/cacheflush.h> #include <asm/hwcap.h> #include <asm/sbi.h> +#include <asm/vector.h> +#include <asm/kvm_vcpu_vector.h> const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = { KVM_GENERIC_VCPU_STATS(), @@ -134,6 +136,8 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu) kvm_riscv_vcpu_fp_reset(vcpu); + kvm_riscv_vcpu_vector_reset(vcpu); + kvm_riscv_vcpu_timer_reset(vcpu); WRITE_ONCE(vcpu->arch.irqs_pending, 0); @@ -189,6 +193,15 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) cntx->hstatus |= HSTATUS_SPVP; cntx->hstatus |= HSTATUS_SPV; + if (has_vector()) { + cntx->vector.datap = kmalloc(riscv_vsize, GFP_KERNEL); + if (!cntx->vector.datap) + return -ENOMEM; + vcpu->arch.host_context.vector.datap = kzalloc(riscv_vsize, GFP_KERNEL); + if (!vcpu->arch.host_context.vector.datap) + return -ENOMEM; + } + /* By default, make CY, TM, and IR counters accessible in VU mode */ reset_csr->scounteren = 0x7; @@ -219,6 +232,9 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) /* Free unused pages pre-allocated for G-stage page table mappings */ kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache); + + /* Free vector context space for host and guest kernel */ + kvm_riscv_vcpu_free_vector_context(vcpu); } int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) @@ -595,6 +611,9 @@ static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu, KVM_REG_RISCV_FP_D); case KVM_REG_RISCV_ISA_EXT: return kvm_riscv_vcpu_set_reg_isa_ext(vcpu, reg); + case KVM_REG_RISCV_VECTOR: + return kvm_riscv_vcpu_set_reg_vector(vcpu, reg, + KVM_REG_RISCV_VECTOR); default: break; } @@ -622,6 +641,9 @@ static int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu, KVM_REG_RISCV_FP_D); case KVM_REG_RISCV_ISA_EXT: return kvm_riscv_vcpu_get_reg_isa_ext(vcpu, reg); + case KVM_REG_RISCV_VECTOR: + return kvm_riscv_vcpu_get_reg_vector(vcpu, reg, + KVM_REG_RISCV_VECTOR); default: break; } @@ -888,6 +910,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) kvm_riscv_vcpu_host_fp_save(&vcpu->arch.host_context); kvm_riscv_vcpu_guest_fp_restore(&vcpu->arch.guest_context, vcpu->arch.isa); + kvm_riscv_vcpu_host_vector_save(&vcpu->arch.host_context); + kvm_riscv_vcpu_guest_vector_restore(&vcpu->arch.guest_context, + vcpu->arch.isa); vcpu->cpu = cpu; } @@ -903,6 +928,11 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) kvm_riscv_vcpu_host_fp_restore(&vcpu->arch.host_context); kvm_riscv_vcpu_timer_save(vcpu); + kvm_riscv_vcpu_guest_vector_save(&vcpu->arch.guest_context, + vcpu->arch.isa); + kvm_riscv_vcpu_host_vector_restore(&vcpu->arch.host_context); + + csr_write(CSR_HGATP, 0); csr->vsstatus = csr_read(CSR_VSSTATUS); csr->vsie = csr_read(CSR_VSIE); diff --git a/arch/riscv/kvm/vcpu_vector.c b/arch/riscv/kvm/vcpu_vector.c new file mode 100644 index 000000000000..a5e6bb126460 --- /dev/null +++ b/arch/riscv/kvm/vcpu_vector.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 Western Digital Corporation or its affiliates. + * Copyright (C) 2022 SiFive + * + * Authors: + * Atish Patra <atish.patra@wdc.com> + * Anup Patel <anup.patel@wdc.com> + * Vincent Chen <vincent.chen@sifive.com> + * Greentime Hu <greentime.hu@sifive.com> + */ + +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/kvm_host.h> +#include <linux/uaccess.h> +#include <asm/hwcap.h> +#include <asm/kvm_vcpu_vector.h> + +#ifdef CONFIG_RISCV_ISA_V +extern unsigned long riscv_vsize; +void kvm_riscv_vcpu_vector_reset(struct kvm_vcpu *vcpu) +{ + unsigned long *isa = vcpu->arch.isa; + struct kvm_cpu_context *cntx = &vcpu->arch.guest_context; + + cntx->sstatus &= ~SR_VS; + if (riscv_isa_extension_available(isa, v)) { + cntx->sstatus |= SR_VS_INITIAL; + WARN_ON(!cntx->vector.datap); + memset(cntx->vector.datap, 0, riscv_vsize); + } else { + cntx->sstatus |= SR_VS_OFF; + } +} + +static void kvm_riscv_vcpu_vector_clean(struct kvm_cpu_context *cntx) +{ + cntx->sstatus &= ~SR_VS; + cntx->sstatus |= SR_VS_CLEAN; +} + +void kvm_riscv_vcpu_guest_vector_save(struct kvm_cpu_context *cntx, + unsigned long *isa) +{ + if ((cntx->sstatus & SR_VS) == SR_VS_DIRTY) { + if (riscv_isa_extension_available(isa, v)) + __kvm_riscv_vector_save(cntx); + kvm_riscv_vcpu_vector_clean(cntx); + } +} + +void kvm_riscv_vcpu_guest_vector_restore(struct kvm_cpu_context *cntx, + unsigned long *isa) +{ + if ((cntx->sstatus & SR_VS) != SR_VS_OFF) { + if (riscv_isa_extension_available(isa, v)) + __kvm_riscv_vector_restore(cntx); + kvm_riscv_vcpu_vector_clean(cntx); + } +} + +void kvm_riscv_vcpu_host_vector_save(struct kvm_cpu_context *cntx) +{ + /* No need to check host sstatus as it can be modified outside */ + if (riscv_isa_extension_available(NULL, v)) + __kvm_riscv_vector_save(cntx); +} + +void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cntx) +{ + if (riscv_isa_extension_available(NULL, v)) + __kvm_riscv_vector_restore(cntx); +} + +void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu) +{ + kfree(vcpu->arch.guest_reset_context.vector.datap); + kfree(vcpu->arch.host_context.vector.datap); +} +#else +#define riscv_vsize (0) +#endif + +static void *kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu, + unsigned long reg_num, + size_t reg_size) +{ + struct kvm_cpu_context *cntx = &vcpu->arch.guest_context; + void *reg_val; + size_t vlenb = riscv_vsize / 32; + + if (reg_num < KVM_REG_RISCV_VECTOR_REG(0)) { + if (reg_size != sizeof(unsigned long)) + return NULL; + switch (reg_num) { + case KVM_REG_RISCV_VECTOR_CSR_REG(vstart): + reg_val = &cntx->vector.vstart; + break; + case KVM_REG_RISCV_VECTOR_CSR_REG(vl): + reg_val = &cntx->vector.vl; + break; + case KVM_REG_RISCV_VECTOR_CSR_REG(vtype): + reg_val = &cntx->vector.vtype; + break; + case KVM_REG_RISCV_VECTOR_CSR_REG(vcsr): + reg_val = &cntx->vector.vcsr; + break; + case KVM_REG_RISCV_VECTOR_CSR_REG(datap): + default: + return NULL; + } + } else if (reg_num <= KVM_REG_RISCV_VECTOR_REG(31)) { + if (reg_size != vlenb) + return NULL; + reg_val = cntx->vector.datap + + (reg_num - KVM_REG_RISCV_VECTOR_REG(0)) * vlenb; + } else { + return NULL; + } + + return reg_val; +} + +int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg, + unsigned long rtype) +{ + unsigned long *isa = vcpu->arch.isa; + unsigned long __user *uaddr = + (unsigned long __user *)(unsigned long)reg->addr; + unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK | + KVM_REG_SIZE_MASK | + rtype); + void *reg_val = NULL; + size_t reg_size = KVM_REG_SIZE(reg->id); + + if (rtype == KVM_REG_RISCV_VECTOR && + riscv_isa_extension_available(isa, v)) { + reg_val = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size); + } + + if (!reg_val) + return -EINVAL; + + if (copy_to_user(uaddr, reg_val, reg_size)) + return -EFAULT; + + return 0; +} + +int kvm_riscv_vcpu_set_reg_vector(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg, + unsigned long rtype) +{ + unsigned long *isa = vcpu->arch.isa; + unsigned long __user *uaddr = + (unsigned long __user *)(unsigned long)reg->addr; + unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK | + KVM_REG_SIZE_MASK | + rtype); + void *reg_val = NULL; + size_t reg_size = KVM_REG_SIZE(reg->id); + + if (rtype == KVM_REG_RISCV_VECTOR && + riscv_isa_extension_available(isa, v)) { + reg_val = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size); + } + + if (!reg_val) + return -EINVAL; + + if (copy_from_user(reg_val, uaddr, reg_size)) + return -EFAULT; + + return 0; +}

[-next,v13,17/19] riscv: KVM: Add vector lazy save/restore support

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