Allow the userspace to set CCSIDR_EL1 so that if the kernel changes the default values of CCSIDR_EL1, the userspace can restore the old values from an old saved VM context.
Suggested-by: Marc Zyngier <[email protected]> Signed-off-by: Akihiko Odaki <[email protected]> --- arch/arm64/include/asm/kvm_host.h | 3 + arch/arm64/kvm/reset.c | 1 + arch/arm64/kvm/sys_regs.c | 116 ++++++++++++++++++++---------- 3 files changed, 83 insertions(+), 37 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index cc2ede0eaed4..cfc6930efe1b 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -417,6 +417,9 @@ struct kvm_vcpu_arch { u64 last_steal; gpa_t base; } steal; + + /* Per-vcpu CCSIDR override or NULL */ + u32 *ccsidr; }; /* diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 5ae18472205a..7980983dbad7 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -157,6 +157,7 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu) if (sve_state) kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu)); kfree(sve_state); + kfree(vcpu->arch.ccsidr); } static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index f4a7c5abcbca..f48a3cc38d24 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -87,11 +87,27 @@ static u32 cache_levels; /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */ #define CSSELR_MAX 14 +static u8 get_min_cache_line_size(u32 csselr) +{ + u64 ctr_el0; + int field; + + ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0); + field = csselr & CSSELR_EL1_InD ? CTR_EL0_IminLine_SHIFT : CTR_EL0_DminLine_SHIFT; + + return cpuid_feature_extract_unsigned_field(ctr_el0, field) - 2; +} + /* Which cache CCSIDR represents depends on CSSELR value. */ -static u32 get_ccsidr(u32 csselr) +static u32 get_ccsidr(struct kvm_vcpu *vcpu, u32 csselr) { + u32 ccsidr_index = csselr & (CSSELR_EL1_Level | CSSELR_EL1_InD); u32 ccsidr; + if (vcpu->arch.ccsidr && is_valid_cache(ccsidr_index) && + !(kvm_has_mte(vcpu->kvm) && (csselr & CSSELR_EL1_TnD))) + return vcpu->arch.ccsidr[ccsidr_index]; + /* Make sure noone else changes CSSELR during this! */ local_irq_disable(); write_sysreg(csselr, csselr_el1); @@ -102,6 +118,61 @@ static u32 get_ccsidr(u32 csselr) return ccsidr; } +static bool is_valid_cache(u32 val) +{ + u32 level, ctype; + + if (val >= CSSELR_MAX) + return false; + + /* Bottom bit is Instruction or Data bit. Next 3 bits are level. */ + level = (val >> 1); + ctype = (cache_levels >> (level * 3)) & 7; + + switch (ctype) { + case 0: /* No cache */ + return false; + case 1: /* Instruction cache only */ + return (val & 1); + case 2: /* Data cache only */ + case 4: /* Unified cache */ + return !(val & 1); + case 3: /* Separate instruction and data caches */ + return true; + default: /* Reserved: we can't know instruction or data. */ + return false; + } +} + +static int set_ccsidr(struct kvm_vcpu *vcpu, u32 csselr, u32 val) +{ + u8 line_size = (val & CCSIDR_EL1_LineSize) >> CCSIDR_EL1_LineSize_SHIFT; + u32 *ccsidr = vcpu->arch.ccsidr; + u32 i; + + if ((val & CCSIDR_EL1_RES0) || line_size < get_min_cache_line_size(csselr)) + return -EINVAL; + + if (!ccsidr) { + if (val == get_ccsidr(vcpu, csselr)) + return 0; + + ccsidr = kmalloc_array(CSSELR_MAX, sizeof(u32), GFP_KERNEL); + if (!ccsidr) + return -ENOMEM; + + for (i = 0; i < CSSELR_MAX; i++) + if (is_valid_cache(i)) + ccsidr[i] = get_ccsidr(vcpu, i); + + vcpu->arch.ccsidr = ccsidr; + } + + ccsidr[csselr] = val; + + return 0; +} + /* * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized). */ @@ -1300,7 +1371,7 @@ static bool access_ccsidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, return write_to_read_only(vcpu, p, r); csselr = vcpu_read_sys_reg(vcpu, CSSELR_EL1); - p->regval = get_ccsidr(csselr); + p->regval = get_ccsidr(vcpu, csselr); /* * Guests should not be doing cache operations by set/way at all, and @@ -2660,33 +2731,7 @@ static int set_invariant_sys_reg(u64 id, u64 __user *uaddr) return 0; } -static bool is_valid_cache(u32 val) -{ - u32 level, ctype; - - if (val >= CSSELR_MAX) - return false; - - /* Bottom bit is Instruction or Data bit. Next 3 bits are level. */ - level = (val >> 1); - ctype = (cache_levels >> (level * 3)) & 7; - - switch (ctype) { - case 0: /* No cache */ - return false; - case 1: /* Instruction cache only */ - return (val & 1); - case 2: /* Data cache only */ - case 4: /* Unified cache */ - return !(val & 1); - case 3: /* Separate instruction and data caches */ - return true; - default: /* Reserved: we can't know instruction or data. */ - return false; - } -} - -static int demux_c15_get(u64 id, void __user *uaddr) +static int demux_c15_get(struct kvm_vcpu *vcpu, u64 id, void __user *uaddr) { u32 val; u32 __user *uval = uaddr; @@ -2705,13 +2750,13 @@ static int demux_c15_get(u64 id, void __user *uaddr) if (!is_valid_cache(val)) return -ENOENT; - return put_user(get_ccsidr(val), uval); + return put_user(get_ccsidr(vcpu, val), uval); default: return -ENOENT; } } -static int demux_c15_set(u64 id, void __user *uaddr) +static int demux_c15_set(struct kvm_vcpu *vcpu, u64 id, void __user *uaddr) { u32 val, newval; u32 __user *uval = uaddr; @@ -2733,10 +2778,7 @@ static int demux_c15_set(u64 id, void __user *uaddr) if (get_user(newval, uval)) return -EFAULT; - /* This is also invariant: you can't change it. */ - if (newval != get_ccsidr(val)) - return -EINVAL; - return 0; + return set_ccsidr(vcpu, val, newval); default: return -ENOENT; } @@ -2773,7 +2815,7 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg int err; if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX) - return demux_c15_get(reg->id, uaddr); + return demux_c15_get(vcpu, reg->id, uaddr); err = get_invariant_sys_reg(reg->id, uaddr); if (err != -ENOENT) @@ -2817,7 +2859,7 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg int err; if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX) - return demux_c15_set(reg->id, uaddr); + return demux_c15_set(vcpu, reg->id, uaddr); err = set_invariant_sys_reg(reg->id, uaddr); if (err != -ENOENT) -- 2.38.1 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
