SME adds a new thread ID register, TPIDR2_EL0. This is used in userspace for delayed saving of the ZA state but in terms of the architecture is not really connected to SME other than being part of FEAT_SME. It has an independent fine grained trap and the runtime connection with the rest of SME is purely software defined.
Expose the register as a system register if the guest supports SME, context switching it along with the other EL0 TPIDRs.
Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 15 +++++++++++++++ arch/arm64/kvm/sys_regs.c | 3 ++- 3 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index edb2acdb4bd1..632c74397fa9 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -450,6 +450,7 @@ enum vcpu_sysreg { CSSELR_EL1, /* Cache Size Selection Register */ TPIDR_EL0, /* Thread ID, User R/W */ TPIDRRO_EL0, /* Thread ID, User R/O */ + TPIDR2_EL0, /* Thread ID, Register 2 */ TPIDR_EL1, /* Thread ID, Privileged */ CNTKCTL_EL1, /* Timer Control Register (EL1) */ PAR_EL1, /* Physical Address Register */ diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h index 5624fd705ae3..8c3b3d6df99f 100644 --- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h +++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h @@ -88,6 +88,17 @@ static inline bool ctxt_has_sctlr2(struct kvm_cpu_context *ctxt) return kvm_has_sctlr2(kern_hyp_va(vcpu->kvm)); }
+static inline bool ctxt_has_sme(struct kvm_cpu_context *ctxt) +{ + struct kvm_vcpu *vcpu; + + if (!system_supports_sme()) + return false; + + vcpu = ctxt_to_vcpu(ctxt); + return kvm_has_sme(kern_hyp_va(vcpu->kvm)); +} + static inline bool ctxt_is_guest(struct kvm_cpu_context *ctxt) { return host_data_ptr(host_ctxt) != ctxt; @@ -127,6 +138,8 @@ static inline void __sysreg_save_user_state(struct kvm_cpu_context *ctxt) { ctxt_sys_reg(ctxt, TPIDR_EL0) = read_sysreg(tpidr_el0); ctxt_sys_reg(ctxt, TPIDRRO_EL0) = read_sysreg(tpidrro_el0); + if (ctxt_has_sme(ctxt)) + ctxt_sys_reg(ctxt, TPIDR2_EL0) = read_sysreg_s(SYS_TPIDR2_EL0); }
static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt) @@ -204,6 +217,8 @@ static inline void __sysreg_restore_user_state(struct kvm_cpu_context *ctxt) { write_sysreg(ctxt_sys_reg(ctxt, TPIDR_EL0), tpidr_el0); write_sysreg(ctxt_sys_reg(ctxt, TPIDRRO_EL0), tpidrro_el0); + if (ctxt_has_sme(ctxt)) + write_sysreg_s(ctxt_sys_reg(ctxt, TPIDR2_EL0), SYS_TPIDR2_EL0); }
static inline void __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt, diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 81742e9237c0..4166d396450d 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -3243,7 +3243,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { .visibility = s1poe_visibility }, { SYS_DESC(SYS_TPIDR_EL0), NULL, reset_unknown, TPIDR_EL0 }, { SYS_DESC(SYS_TPIDRRO_EL0), NULL, reset_unknown, TPIDRRO_EL0 }, - { SYS_DESC(SYS_TPIDR2_EL0), undef_access }, + { SYS_DESC(SYS_TPIDR2_EL0), NULL, reset_unknown, TPIDR2_EL0, + .visibility = sme_visibility},
{ SYS_DESC(SYS_SCXTNUM_EL0), undef_access },