diff options
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 5 | ||||
| -rw-r--r-- | arch/arm64/include/asm/sysreg.h | 8 | ||||
| -rw-r--r-- | arch/arm64/kvm/debug.c | 26 | ||||
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 74 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/aarch64/debug-exceptions.c | 58 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/aarch64/get-reg-list.c | 1 |
6 files changed, 149 insertions, 23 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 4866842c31e1..02781e538cfc 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -173,6 +173,7 @@ enum vcpu_sysreg { PAR_EL1, /* Physical Address Register */ MDSCR_EL1, /* Monitor Debug System Control Register */ MDCCINT_EL1, /* Monitor Debug Comms Channel Interrupt Enable Reg */ + OSLSR_EL1, /* OS Lock Status Register */ DISR_EL1, /* Deferred Interrupt Status Register */ /* Performance Monitors Registers */ @@ -727,6 +728,10 @@ void kvm_arm_vcpu_init_debug(struct kvm_vcpu *vcpu); void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); void kvm_arm_clear_debug(struct kvm_vcpu *vcpu); void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu); + +#define kvm_vcpu_os_lock_enabled(vcpu) \ + (!!(__vcpu_sys_reg(vcpu, OSLSR_EL1) & SYS_OSLSR_OSLK)) + int kvm_arm_vcpu_arch_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu, diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 898bee0004ae..906a3550fc50 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -128,8 +128,16 @@ #define SYS_DBGWVRn_EL1(n) sys_reg(2, 0, 0, n, 6) #define SYS_DBGWCRn_EL1(n) sys_reg(2, 0, 0, n, 7) #define SYS_MDRAR_EL1 sys_reg(2, 0, 1, 0, 0) + #define SYS_OSLAR_EL1 sys_reg(2, 0, 1, 0, 4) +#define SYS_OSLAR_OSLK BIT(0) + #define SYS_OSLSR_EL1 sys_reg(2, 0, 1, 1, 4) +#define SYS_OSLSR_OSLM_MASK (BIT(3) | BIT(0)) +#define SYS_OSLSR_OSLM_NI 0 +#define SYS_OSLSR_OSLM_IMPLEMENTED BIT(3) +#define SYS_OSLSR_OSLK BIT(1) + #define SYS_OSDLR_EL1 sys_reg(2, 0, 1, 3, 4) #define SYS_DBGPRCR_EL1 sys_reg(2, 0, 1, 4, 4) #define SYS_DBGCLAIMSET_EL1 sys_reg(2, 0, 7, 8, 6) diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index db9361338b2a..4fd5c216c4bb 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -105,9 +105,11 @@ static void kvm_arm_setup_mdcr_el2(struct kvm_vcpu *vcpu) * - Userspace is using the hardware to debug the guest * (KVM_GUESTDBG_USE_HW is set). * - The guest is not using debug (KVM_ARM64_DEBUG_DIRTY is clear). + * - The guest has enabled the OS Lock (debug exceptions are blocked). */ if ((vcpu->guest_debug & KVM_GUESTDBG_USE_HW) || - !(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)) + !(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY) || + kvm_vcpu_os_lock_enabled(vcpu)) vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2); @@ -160,8 +162,8 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) kvm_arm_setup_mdcr_el2(vcpu); - /* Is Guest debugging in effect? */ - if (vcpu->guest_debug) { + /* Check if we need to use the debug registers. */ + if (vcpu->guest_debug || kvm_vcpu_os_lock_enabled(vcpu)) { /* Save guest debug state */ save_guest_debug_regs(vcpu); @@ -223,6 +225,19 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) trace_kvm_arm_set_regset("WAPTS", get_num_wrps(), &vcpu->arch.debug_ptr->dbg_wcr[0], &vcpu->arch.debug_ptr->dbg_wvr[0]); + + /* + * The OS Lock blocks debug exceptions in all ELs when it is + * enabled. If the guest has enabled the OS Lock, constrain its + * effects to the guest. Emulate the behavior by clearing + * MDSCR_EL1.MDE. In so doing, we ensure that host debug + * exceptions are unaffected by guest configuration of the OS + * Lock. + */ + } else if (kvm_vcpu_os_lock_enabled(vcpu)) { + mdscr = vcpu_read_sys_reg(vcpu, MDSCR_EL1); + mdscr &= ~DBG_MDSCR_MDE; + vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1); } } @@ -244,7 +259,10 @@ void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) { trace_kvm_arm_clear_debug(vcpu->guest_debug); - if (vcpu->guest_debug) { + /* + * Restore the guest's debug registers if we were using them. + */ + if (vcpu->guest_debug || kvm_vcpu_os_lock_enabled(vcpu)) { restore_guest_debug_regs(vcpu); /* diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 4dc2fba316ff..dd34b5ab51d4 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -44,6 +44,10 @@ * 64bit interface. */ +static int reg_from_user(u64 *val, const void __user *uaddr, u64 id); +static int reg_to_user(void __user *uaddr, const u64 *val, u64 id); +static u64 sys_reg_to_index(const struct sys_reg_desc *reg); + static bool read_from_write_only(struct kvm_vcpu *vcpu, struct sys_reg_params *params, const struct sys_reg_desc *r) @@ -287,16 +291,55 @@ static bool trap_loregion(struct kvm_vcpu *vcpu, return trap_raz_wi(vcpu, p, r); } +static bool trap_oslar_el1(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + u64 oslsr; + + if (!p->is_write) + return read_from_write_only(vcpu, p, r); + + /* Forward the OSLK bit to OSLSR */ + oslsr = __vcpu_sys_reg(vcpu, OSLSR_EL1) & ~SYS_OSLSR_OSLK; + if (p->regval & SYS_OSLAR_OSLK) + oslsr |= SYS_OSLSR_OSLK; + + __vcpu_sys_reg(vcpu, OSLSR_EL1) = oslsr; + return true; +} + static bool trap_oslsr_el1(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { - if (p->is_write) { - return ignore_write(vcpu, p); - } else { - p->regval = (1 << 3); - return true; - } + if (p->is_write) + return write_to_read_only(vcpu, p, r); + + p->regval = __vcpu_sys_reg(vcpu, r->reg); + return true; +} + +static int set_oslsr_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, + const struct kvm_one_reg *reg, void __user *uaddr) +{ + u64 id = sys_reg_to_index(rd); + u64 val; + int err; + + err = reg_from_user(&val, uaddr, id); + if (err) + return err; + + /* + * The only modifiable bit is the OSLK bit. Refuse the write if + * userspace attempts to change any other bit in the register. + */ + if ((val ^ rd->val) & ~SYS_OSLSR_OSLK) + return -EINVAL; + + __vcpu_sys_reg(vcpu, rd->reg) = val; + return 0; } static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu, @@ -1164,10 +1207,6 @@ static bool access_raz_id_reg(struct kvm_vcpu *vcpu, return __access_id_reg(vcpu, p, r, true); } -static int reg_from_user(u64 *val, const void __user *uaddr, u64 id); -static int reg_to_user(void __user *uaddr, const u64 *val, u64 id); -static u64 sys_reg_to_index(const struct sys_reg_desc *reg); - /* Visibility overrides for SVE-specific control registers */ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd) @@ -1418,9 +1457,9 @@ static unsigned int mte_visibility(const struct kvm_vcpu *vcpu, * Debug handling: We do trap most, if not all debug related system * registers. The implementation is good enough to ensure that a guest * can use these with minimal performance degradation. The drawback is - * that we don't implement any of the external debug, none of the - * OSlock protocol. This should be revisited if we ever encounter a - * more demanding guest... + * that we don't implement any of the external debug architecture. + * This should be revisited if we ever encounter a more demanding + * guest... */ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_DC_ISW), access_dcsw }, @@ -1447,8 +1486,9 @@ static const struct sys_reg_desc sys_reg_descs[] = { DBG_BCR_BVR_WCR_WVR_EL1(15), { SYS_DESC(SYS_MDRAR_EL1), trap_raz_wi }, - { SYS_DESC(SYS_OSLAR_EL1), trap_raz_wi }, - { SYS_DESC(SYS_OSLSR_EL1), trap_oslsr_el1 }, + { SYS_DESC(SYS_OSLAR_EL1), trap_oslar_el1 }, + { SYS_DESC(SYS_OSLSR_EL1), trap_oslsr_el1, reset_val, OSLSR_EL1, + SYS_OSLSR_OSLM_IMPLEMENTED, .set_user = set_oslsr_el1, }, { SYS_DESC(SYS_OSDLR_EL1), trap_raz_wi }, { SYS_DESC(SYS_DBGPRCR_EL1), trap_raz_wi }, { SYS_DESC(SYS_DBGCLAIMSET_EL1), trap_raz_wi }, @@ -1920,10 +1960,10 @@ static const struct sys_reg_desc cp14_regs[] = { DBGBXVR(0), /* DBGOSLAR */ - { Op1( 0), CRn( 1), CRm( 0), Op2( 4), trap_raz_wi }, + { Op1( 0), CRn( 1), CRm( 0), Op2( 4), trap_oslar_el1 }, DBGBXVR(1), /* DBGOSLSR */ - { Op1( 0), CRn( 1), CRm( 1), Op2( 4), trap_oslsr_el1 }, + { Op1( 0), CRn( 1), CRm( 1), Op2( 4), trap_oslsr_el1, NULL, OSLSR_EL1 }, DBGBXVR(2), DBGBXVR(3), /* DBGOSDLR */ diff --git a/tools/testing/selftests/kvm/aarch64/debug-exceptions.c b/tools/testing/selftests/kvm/aarch64/debug-exceptions.c index ea189d83abf7..63b2178210c4 100644 --- a/tools/testing/selftests/kvm/aarch64/debug-exceptions.c +++ b/tools/testing/selftests/kvm/aarch64/debug-exceptions.c @@ -23,7 +23,7 @@ #define SPSR_D (1 << 9) #define SPSR_SS (1 << 21) -extern unsigned char sw_bp, hw_bp, bp_svc, bp_brk, hw_wp, ss_start; +extern unsigned char sw_bp, sw_bp2, hw_bp, hw_bp2, bp_svc, bp_brk, hw_wp, ss_start; static volatile uint64_t sw_bp_addr, hw_bp_addr; static volatile uint64_t wp_addr, wp_data_addr; static volatile uint64_t svc_addr; @@ -47,6 +47,14 @@ static void reset_debug_state(void) isb(); } +static void enable_os_lock(void) +{ + write_sysreg(1, oslar_el1); + isb(); + + GUEST_ASSERT(read_sysreg(oslsr_el1) & 2); +} + static void install_wp(uint64_t addr) { uint32_t wcr; @@ -99,6 +107,7 @@ static void guest_code(void) GUEST_SYNC(0); /* Software-breakpoint */ + reset_debug_state(); asm volatile("sw_bp: brk #0"); GUEST_ASSERT_EQ(sw_bp_addr, PC(sw_bp)); @@ -152,6 +161,51 @@ static void guest_code(void) GUEST_ASSERT_EQ(ss_addr[1], PC(ss_start) + 4); GUEST_ASSERT_EQ(ss_addr[2], PC(ss_start) + 8); + GUEST_SYNC(6); + + /* OS Lock does not block software-breakpoint */ + reset_debug_state(); + enable_os_lock(); + sw_bp_addr = 0; + asm volatile("sw_bp2: brk #0"); + GUEST_ASSERT_EQ(sw_bp_addr, PC(sw_bp2)); + + GUEST_SYNC(7); + + /* OS Lock blocking hardware-breakpoint */ + reset_debug_state(); + enable_os_lock(); + install_hw_bp(PC(hw_bp2)); + hw_bp_addr = 0; + asm volatile("hw_bp2: nop"); + GUEST_ASSERT_EQ(hw_bp_addr, 0); + + GUEST_SYNC(8); + + /* OS Lock blocking watchpoint */ + reset_debug_state(); + enable_os_lock(); + write_data = '\0'; + wp_data_addr = 0; + install_wp(PC(write_data)); + write_data = 'x'; + GUEST_ASSERT_EQ(write_data, 'x'); + GUEST_ASSERT_EQ(wp_data_addr, 0); + + GUEST_SYNC(9); + + /* OS Lock blocking single-step */ + reset_debug_state(); + enable_os_lock(); + ss_addr[0] = 0; + install_ss(); + ss_idx = 0; + asm volatile("mrs x0, esr_el1\n\t" + "add x0, x0, #1\n\t" + "msr daifset, #8\n\t" + : : : "x0"); + GUEST_ASSERT_EQ(ss_addr[0], 0); + GUEST_DONE(); } @@ -223,7 +277,7 @@ int main(int argc, char *argv[]) vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT, ESR_EC_SVC64, guest_svc_handler); - for (stage = 0; stage < 7; stage++) { + for (stage = 0; stage < 11; stage++) { vcpu_run(vm, VCPU_ID); switch (get_ucall(vm, VCPU_ID, &uc)) { diff --git a/tools/testing/selftests/kvm/aarch64/get-reg-list.c b/tools/testing/selftests/kvm/aarch64/get-reg-list.c index f769fc6cd927..f12147c43464 100644 --- a/tools/testing/selftests/kvm/aarch64/get-reg-list.c +++ b/tools/testing/selftests/kvm/aarch64/get-reg-list.c @@ -760,6 +760,7 @@ static __u64 base_regs[] = { ARM64_SYS_REG(2, 0, 0, 15, 5), ARM64_SYS_REG(2, 0, 0, 15, 6), ARM64_SYS_REG(2, 0, 0, 15, 7), + ARM64_SYS_REG(2, 0, 1, 1, 4), /* OSLSR_EL1 */ ARM64_SYS_REG(2, 4, 0, 7, 0), /* DBGVCR32_EL2 */ ARM64_SYS_REG(3, 0, 0, 0, 5), /* MPIDR_EL1 */ ARM64_SYS_REG(3, 0, 0, 1, 0), /* ID_PFR0_EL1 */ |