Define the new system registers that MTE introduces and context switch
them. Also hide the MTE feature from the ID register as it isn't
supported in a VM yet.

Signed-off-by: Steven Price <steven.pr...@arm.com>
---
 arch/arm64/include/asm/kvm_host.h |  7 +++++++
 arch/arm64/kvm/hyp/sysreg-sr.c    | 12 ++++++++++++
 arch/arm64/kvm/sys_regs.c         |  7 +++++++
 3 files changed, 26 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h 
b/arch/arm64/include/asm/kvm_host.h
index 32c8a675e5a4..1f10e9dee2e0 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -92,6 +92,9 @@ struct kvm_arch {
         * supported.
         */
        bool return_nisv_io_abort_to_user;
+
+       /* If any VCPU has MTE enabled then all memory must be MTE enabled */
+       bool vcpu_has_mte;
 };
 
 #define KVM_NR_MEM_OBJS     40
@@ -123,6 +126,8 @@ enum vcpu_sysreg {
        SCTLR_EL1,      /* System Control Register */
        ACTLR_EL1,      /* Auxiliary Control Register */
        CPACR_EL1,      /* Coprocessor Access Control */
+       RGSR_EL1,       /* Random Allocation Tag Seed Register */
+       GCR_EL1,        /* Tag Control Register */
        ZCR_EL1,        /* SVE Control */
        TTBR0_EL1,      /* Translation Table Base Register 0 */
        TTBR1_EL1,      /* Translation Table Base Register 1 */
@@ -139,6 +144,8 @@ enum vcpu_sysreg {
        TPIDR_EL1,      /* Thread ID, Privileged */
        AMAIR_EL1,      /* Aux Memory Attribute Indirection Register */
        CNTKCTL_EL1,    /* Timer Control Register (EL1) */
+       TFSRE0_EL1,     /* Tag Fault Status Register (EL0) */
+       TFSR_EL1,       /* Tag Fault Stauts Register (EL1) */
        PAR_EL1,        /* Physical Address Register */
        MDSCR_EL1,      /* Monitor Debug System Control Register */
        MDCCINT_EL1,    /* Monitor Debug Comms Channel Interrupt Enable Reg */
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 75b1925763f1..6ecee1528566 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -26,6 +26,12 @@
 static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
 {
        ctxt->sys_regs[MDSCR_EL1]       = read_sysreg(mdscr_el1);
+       if (system_supports_mte()) {
+               ctxt->sys_regs[RGSR_EL1] = read_sysreg_s(SYS_RGSR_EL1);
+               ctxt->sys_regs[GCR_EL1] = read_sysreg_s(SYS_GCR_EL1);
+               ctxt->sys_regs[TFSRE0_EL1] = read_sysreg_s(SYS_TFSRE0_EL1);
+               ctxt->sys_regs[TFSR_EL1] = read_sysreg_s(SYS_TFSR_EL1);
+       }
 
        /*
         * The host arm64 Linux uses sp_el0 to point to 'current' and it must
@@ -99,6 +105,12 @@ NOKPROBE_SYMBOL(sysreg_save_guest_state_vhe);
 static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context 
*ctxt)
 {
        write_sysreg(ctxt->sys_regs[MDSCR_EL1],   mdscr_el1);
+       if (system_supports_mte()) {
+               write_sysreg_s(ctxt->sys_regs[RGSR_EL1], SYS_RGSR_EL1);
+               write_sysreg_s(ctxt->sys_regs[GCR_EL1], SYS_GCR_EL1);
+               write_sysreg_s(ctxt->sys_regs[TFSRE0_EL1], SYS_TFSRE0_EL1);
+               write_sysreg_s(ctxt->sys_regs[TFSR_EL1], SYS_TFSR_EL1);
+       }
 
        /*
         * The host arm64 Linux uses sp_el0 to point to 'current' and it must
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 51db934702b6..3ae008a9b0bd 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1095,6 +1095,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
                if (!vcpu_has_sve(vcpu))
                        val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
                val &= ~(0xfUL << ID_AA64PFR0_AMU_SHIFT);
+       } else if (id == SYS_ID_AA64PFR1_EL1) {
+               val &= ~(0xfUL << ID_AA64PFR1_MTE_SHIFT);
        } else if (id == SYS_ID_AA64ISAR1_EL1 && !vcpu_has_ptrauth(vcpu)) {
                val &= ~((0xfUL << ID_AA64ISAR1_APA_SHIFT) |
                         (0xfUL << ID_AA64ISAR1_API_SHIFT) |
@@ -1504,6 +1506,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 
        { SYS_DESC(SYS_SCTLR_EL1), access_vm_reg, reset_val, SCTLR_EL1, 
0x00C50078 },
        { SYS_DESC(SYS_CPACR_EL1), NULL, reset_val, CPACR_EL1, 0 },
+       { SYS_DESC(SYS_RGSR_EL1), trap_raz_wi, reset_unknown, RGSR_EL1 },
+       { SYS_DESC(SYS_GCR_EL1), trap_raz_wi, reset_unknown, GCR_EL1 },
        { SYS_DESC(SYS_ZCR_EL1), NULL, reset_val, ZCR_EL1, 0, .visibility = 
sve_visibility },
        { SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 },
        { SYS_DESC(SYS_TTBR1_EL1), access_vm_reg, reset_unknown, TTBR1_EL1 },
@@ -1528,6 +1532,9 @@ static const struct sys_reg_desc sys_reg_descs[] = {
        { SYS_DESC(SYS_ERXMISC0_EL1), trap_raz_wi },
        { SYS_DESC(SYS_ERXMISC1_EL1), trap_raz_wi },
 
+       { SYS_DESC(SYS_TFSR_EL1), trap_raz_wi, reset_unknown, TFSR_EL1 },
+       { SYS_DESC(SYS_TFSRE0_EL1), trap_raz_wi, reset_unknown, TFSRE0_EL1 },
+
        { SYS_DESC(SYS_FAR_EL1), access_vm_reg, reset_unknown, FAR_EL1 },
        { SYS_DESC(SYS_PAR_EL1), NULL, reset_unknown, PAR_EL1 },
 
-- 
2.20.1

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