diff options
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 11 | ||||
| -rw-r--r-- | arch/arm64/kvm/arm.c | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/debug.c | 46 | ||||
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 2 |
4 files changed, 60 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index d196bf0fce52..f65b30bab0ab 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -756,6 +756,12 @@ struct kvm_vcpu_arch { struct kvm_guest_debug_arch vcpu_debug_state; struct kvm_guest_debug_arch external_debug_state; + enum { + VCPU_DEBUG_FREE, + VCPU_DEBUG_HOST_OWNED, + VCPU_DEBUG_GUEST_OWNED, + } debug_owner; + /* VGIC state */ struct vgic_cpu vgic_cpu; struct arch_timer_cpu timer_cpu; @@ -1345,10 +1351,15 @@ 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); +void kvm_vcpu_load_debug(struct kvm_vcpu *vcpu); +void kvm_debug_set_guest_ownership(struct kvm_vcpu *vcpu); #define kvm_vcpu_os_lock_enabled(vcpu) \ (!!(__vcpu_sys_reg(vcpu, OSLSR_EL1) & OSLSR_EL1_OSLK)) +#define kvm_host_owns_debug_regs(vcpu) \ + ((vcpu)->arch.debug_owner == VCPU_DEBUG_HOST_OWNED) + 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/kvm/arm.c b/arch/arm64/kvm/arm.c index 3822774840e1..a068337da52a 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -598,6 +598,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) kvm_vgic_load(vcpu); kvm_timer_vcpu_load(vcpu); + kvm_vcpu_load_debug(vcpu); if (has_vhe()) kvm_vcpu_load_vhe(vcpu); kvm_arch_vcpu_load_fp(vcpu); diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index fef03456284b..548016439aca 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -317,3 +317,49 @@ void kvm_init_host_debug_data(void) !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_EL1_P)) host_data_set_flag(HAS_TRBE); } + +void kvm_vcpu_load_debug(struct kvm_vcpu *vcpu) +{ + u64 mdscr; + + /* Must be called before kvm_vcpu_load_vhe() */ + KVM_BUG_ON(vcpu_get_flag(vcpu, SYSREGS_ON_CPU), vcpu->kvm); + + /* + * Determine which of the possible debug states we're in: + * + * - VCPU_DEBUG_HOST_OWNED: KVM has taken ownership of the guest's + * breakpoint/watchpoint registers, or needs to use MDSCR_EL1 to do + * software step or emulate the effects of the OS Lock being enabled. + * + * - VCPU_DEBUG_GUEST_OWNED: The guest has debug exceptions enabled, and + * the breakpoint/watchpoint registers need to be loaded eagerly. + * + * - VCPU_DEBUG_FREE: Neither of the above apply, no breakpoint/watchpoint + * context needs to be loaded on the CPU. + */ + if (vcpu->guest_debug || kvm_vcpu_os_lock_enabled(vcpu)) { + vcpu->arch.debug_owner = VCPU_DEBUG_HOST_OWNED; + } else { + mdscr = vcpu_read_sys_reg(vcpu, MDSCR_EL1); + + if (mdscr & (MDSCR_EL1_KDE | MDSCR_EL1_MDE)) + vcpu->arch.debug_owner = VCPU_DEBUG_GUEST_OWNED; + else + vcpu->arch.debug_owner = VCPU_DEBUG_FREE; + } +} + +/* + * Updates ownership of the debug registers after a trapped guest access to a + * breakpoint/watchpoint register. Host ownership of the debug registers is of + * strictly higher priority, and it is the responsibility of the VMM to emulate + * guest debug exceptions in this configuration. + */ +void kvm_debug_set_guest_ownership(struct kvm_vcpu *vcpu) +{ + if (kvm_host_owns_debug_regs(vcpu)) + return; + + vcpu->arch.debug_owner = VCPU_DEBUG_GUEST_OWNED; +} diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index e2a5c2918d9e..e45a096be669 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -656,6 +656,7 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu, if (p->is_write) vcpu_set_flag(vcpu, DEBUG_DIRTY); + kvm_debug_set_guest_ownership(vcpu); trace_trap_reg(__func__, r->reg, p->is_write, p->regval); return true; @@ -684,6 +685,7 @@ static void reg_to_dbg(struct kvm_vcpu *vcpu, val |= (p->regval & (mask >> shift)) << shift; *dbg_reg = val; + kvm_debug_set_guest_ownership(vcpu); vcpu_set_flag(vcpu, DEBUG_DIRTY); } |