diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 905b84e59c24..a6796a952af7 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -917,8 +917,6 @@ struct kvm_vcpu_arch { #define EXCEPT_AA64_EL2_IRQ __vcpu_except_flags(5) #define EXCEPT_AA64_EL2_FIQ __vcpu_except_flags(6) #define EXCEPT_AA64_EL2_SERR __vcpu_except_flags(7) -/* Guest debug is live */ -#define DEBUG_DIRTY __vcpu_single_flag(iflags, BIT(4)) /* Physical CPU not in supported_cpus */ #define ON_UNSUPPORTED_CPU __vcpu_single_flag(sflags, BIT(0)) @@ -1356,6 +1354,8 @@ void kvm_debug_set_guest_ownership(struct kvm_vcpu *vcpu); ((vcpu)->arch.debug_owner != VCPU_DEBUG_FREE) #define kvm_host_owns_debug_regs(vcpu) \ ((vcpu)->arch.debug_owner == VCPU_DEBUG_HOST_OWNED) +#define kvm_guest_owns_debug_regs(vcpu) \ + ((vcpu)->arch.debug_owner == VCPU_DEBUG_GUEST_OWNED) int kvm_arm_vcpu_arch_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index f39004c52d33..a4ae17c31fa8 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -86,15 +86,9 @@ static void kvm_arm_setup_mdcr_el2(struct kvm_vcpu *vcpu) vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE; /* - * Trap debug register access when one of the following is true: - * - Userspace is using the hardware to debug the guest - * (KVM_GUESTDBG_USE_HW is set). - * - The guest is not using debug (DEBUG_DIRTY clear). - * - The guest has enabled the OS Lock (debug exceptions are blocked). + * Trap debug registers if the guest doesn't have ownership of them. */ - if ((vcpu->guest_debug & KVM_GUESTDBG_USE_HW) || - !vcpu_get_flag(vcpu, DEBUG_DIRTY) || - kvm_vcpu_os_lock_enabled(vcpu)) + if (!kvm_guest_owns_debug_regs(vcpu)) vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; /* Write MDCR_EL2 directly if we're already at EL2 */ @@ -127,8 +121,7 @@ void kvm_arm_vcpu_init_debug(struct kvm_vcpu *vcpu) * debug related registers. * * Additionally, KVM only traps guest accesses to the debug registers if - * the guest is not actively using them (see the DEBUG_DIRTY - * flag on vcpu->arch.iflags). Since the guest must not interfere + * the guest is not actively using them. Since the guest must not interfere * with the hardware state when debugging the guest, we must ensure that * trapping is enabled whenever we are debugging the guest using the * debug registers. @@ -195,8 +188,6 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) mdscr |= DBG_MDSCR_MDE; vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1); - vcpu_set_flag(vcpu, DEBUG_DIRTY); - /* * The OS Lock blocks debug exceptions in all ELs when it is * enabled. If the guest has enabled the OS Lock, constrain its @@ -211,10 +202,6 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1); } } - - /* If KDE or MDE are set, perform a full save/restore cycle. */ - if (vcpu_read_sys_reg(vcpu, MDSCR_EL1) & (DBG_MDSCR_KDE | DBG_MDSCR_MDE)) - vcpu_set_flag(vcpu, DEBUG_DIRTY); } void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h index 9e3051225039..c14586d87361 100644 --- a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h +++ b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h @@ -176,8 +176,6 @@ static inline void __debug_switch_to_host_common(struct kvm_vcpu *vcpu) __debug_save_state(guest_dbg, guest_ctxt); __debug_restore_state(host_dbg, host_ctxt); - - vcpu_clear_flag(vcpu, DEBUG_DIRTY); } #endif /* __ARM64_KVM_HYP_DEBUG_SR_H__ */ diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h index a651c43ad679..a998b2f6abcb 100644 --- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h +++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h @@ -283,7 +283,7 @@ static inline void __sysreg32_save_state(struct kvm_vcpu *vcpu) __vcpu_sys_reg(vcpu, DACR32_EL2) = read_sysreg(dacr32_el2); __vcpu_sys_reg(vcpu, IFSR32_EL2) = read_sysreg(ifsr32_el2); - if (has_vhe() || vcpu_get_flag(vcpu, DEBUG_DIRTY)) + if (has_vhe() || kvm_debug_regs_in_use(vcpu)) __vcpu_sys_reg(vcpu, DBGVCR32_EL2) = read_sysreg(dbgvcr32_el2); } @@ -300,7 +300,7 @@ static inline void __sysreg32_restore_state(struct kvm_vcpu *vcpu) write_sysreg(__vcpu_sys_reg(vcpu, DACR32_EL2), dacr32_el2); write_sysreg(__vcpu_sys_reg(vcpu, IFSR32_EL2), ifsr32_el2); - if (has_vhe() || vcpu_get_flag(vcpu, DEBUG_DIRTY)) + if (has_vhe() || kvm_debug_regs_in_use(vcpu)) write_sysreg(__vcpu_sys_reg(vcpu, DBGVCR32_EL2), dbgvcr32_el2); } diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 8c5771572133..66db77fb6201 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -621,40 +621,11 @@ static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu, } } -/* - * We want to avoid world-switching all the DBG registers all the - * time: - * - * - If we've touched any debug register, it is likely that we're - * going to touch more of them. It then makes sense to disable the - * traps and start doing the save/restore dance - * - If debug is active (DBG_MDSCR_KDE or DBG_MDSCR_MDE set), it is - * then mandatory to save/restore the registers, as the guest - * depends on them. - * - * For this, we use a DIRTY bit, indicating the guest has modified the - * debug registers, used as follow: - * - * On guest entry: - * - If the dirty bit is set (because we're coming back from trapping), - * disable the traps, save host registers, restore guest registers. - * - If debug is actively in use (DBG_MDSCR_KDE or DBG_MDSCR_MDE set), - * set the dirty bit, disable the traps, save host registers, - * restore guest registers. - * - Otherwise, enable the traps - * - * On guest exit: - * - If the dirty bit is set, save guest registers, restore host - * registers and clear the dirty bit. This ensure that the host can - * now use the debug registers. - */ static bool trap_debug_regs(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { access_rw(vcpu, p, r); - if (p->is_write) - vcpu_set_flag(vcpu, DEBUG_DIRTY); kvm_debug_set_guest_ownership(vcpu); return true; @@ -665,9 +636,6 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu, * * A 32 bit write to a debug register leave top bits alone * A 32 bit read from a debug register only returns the bottom bits - * - * All writes will set the DEBUG_DIRTY flag to ensure the hyp code - * switches between host and guest values in future. */ static void reg_to_dbg(struct kvm_vcpu *vcpu, struct sys_reg_params *p, @@ -684,7 +652,6 @@ static void reg_to_dbg(struct kvm_vcpu *vcpu, *dbg_reg = val; kvm_debug_set_guest_ownership(vcpu); - vcpu_set_flag(vcpu, DEBUG_DIRTY); } static void dbg_to_reg(struct kvm_vcpu *vcpu,