From: Oliver Upton Date: Thu, 20 Jun 2024 16:46:40 +0000 (+0000) Subject: KVM: arm64: nv: Handle ZCR_EL2 traps X-Git-Tag: v6.11-rc1~89^2~17^2~2^2~12 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b3d29a8230998b36afecf494b199211d26052785;p=thirdparty%2Flinux.git KVM: arm64: nv: Handle ZCR_EL2 traps Unlike other SVE-related registers, ZCR_EL2 takes a sysreg trap to EL2 when HCR_EL2.NV = 1. KVM still needs to honor the guest hypervisor's trap configuration, which expects an SVE trap (i.e. ESR_EL2.EC = 0x19) when CPTR traps are enabled for the vCPU's current context. Otherwise, if the guest hypervisor has traps disabled, emulate the access by mapping the requested VL into ZCR_EL1. Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20240620164653.1130714-4-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index befef5d0daae3..c5fa66f5fd823 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -56,6 +56,14 @@ void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu); int kvm_inject_nested_sync(struct kvm_vcpu *vcpu, u64 esr_el2); int kvm_inject_nested_irq(struct kvm_vcpu *vcpu); +static inline void kvm_inject_nested_sve_trap(struct kvm_vcpu *vcpu) +{ + u64 esr = FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SVE) | + ESR_ELx_IL; + + kvm_inject_nested_sync(vcpu, esr); +} + #if defined(__KVM_VHE_HYPERVISOR__) || defined(__KVM_NVHE_HYPERVISOR__) static __always_inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu) { diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 36b8e97bf49ec..0ff1ed1341fc1 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -423,6 +423,7 @@ enum vcpu_sysreg { MDCR_EL2, /* Monitor Debug Configuration Register (EL2) */ CPTR_EL2, /* Architectural Feature Trap Register (EL2) */ HACR_EL2, /* Hypervisor Auxiliary Control Register */ + ZCR_EL2, /* SVE Control Register (EL2) */ TTBR0_EL2, /* Translation Table Base Register 0 (EL2) */ TTBR1_EL2, /* Translation Table Base Register 1 (EL2) */ TCR_EL2, /* Translation Control Register (EL2) */ @@ -991,6 +992,7 @@ static inline bool __vcpu_read_sys_reg_from_cpu(int reg, u64 *val) case DACR32_EL2: *val = read_sysreg_s(SYS_DACR32_EL2); break; case IFSR32_EL2: *val = read_sysreg_s(SYS_IFSR32_EL2); break; case DBGVCR32_EL2: *val = read_sysreg_s(SYS_DBGVCR32_EL2); break; + case ZCR_EL1: *val = read_sysreg_s(SYS_ZCR_EL12); break; default: return false; } @@ -1036,6 +1038,7 @@ static inline bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg) case DACR32_EL2: write_sysreg_s(val, SYS_DACR32_EL2); break; case IFSR32_EL2: write_sysreg_s(val, SYS_IFSR32_EL2); break; case DBGVCR32_EL2: write_sysreg_s(val, SYS_DBGVCR32_EL2); break; + case ZCR_EL1: write_sysreg_s(val, SYS_ZCR_EL12); break; default: return false; } diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 22b45a15d0688..80aa99a012ae1 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -121,6 +121,7 @@ static bool get_el2_to_el1_mapping(unsigned int reg, MAPPED_EL2_SYSREG(AMAIR_EL2, AMAIR_EL1, NULL ); MAPPED_EL2_SYSREG(ELR_EL2, ELR_EL1, NULL ); MAPPED_EL2_SYSREG(SPSR_EL2, SPSR_EL1, NULL ); + MAPPED_EL2_SYSREG(ZCR_EL2, ZCR_EL1, NULL ); default: return false; } @@ -2199,6 +2200,40 @@ static u64 reset_hcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) return __vcpu_sys_reg(vcpu, r->reg) = val; } +static unsigned int sve_el2_visibility(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd) +{ + unsigned int r; + + r = el2_visibility(vcpu, rd); + if (r) + return r; + + return sve_visibility(vcpu, rd); +} + +static bool access_zcr_el2(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + unsigned int vq; + + if (guest_hyp_sve_traps_enabled(vcpu)) { + kvm_inject_nested_sve_trap(vcpu); + return true; + } + + if (!p->is_write) { + p->regval = vcpu_read_sys_reg(vcpu, ZCR_EL2); + return true; + } + + vq = SYS_FIELD_GET(ZCR_ELx, LEN, p->regval) + 1; + vq = min(vq, vcpu_sve_max_vq(vcpu)); + vcpu_write_sys_reg(vcpu, vq - 1, ZCR_EL2); + return true; +} + /* * Architected system registers. * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2 @@ -2688,6 +2723,9 @@ static const struct sys_reg_desc sys_reg_descs[] = { EL2_REG_VNCR(HFGITR_EL2, reset_val, 0), EL2_REG_VNCR(HACR_EL2, reset_val, 0), + { SYS_DESC(SYS_ZCR_EL2), .access = access_zcr_el2, .reset = reset_val, + .visibility = sve_el2_visibility, .reg = ZCR_EL2 }, + EL2_REG_VNCR(HCRX_EL2, reset_val, 0), EL2_REG(TTBR0_EL2, access_rw, reset_val, 0),