When we are using the hardware registers for guest debug we need to deal with the guests access to them. There is already a mechanism for dealing with these accesses so we build on top of that.
- mdscr_el1_bits is renamed as we save the whole register - any access to mdscr_el1 is now stored in the mirror location - if we are using HW assisted debug we do the same with DBG[WB][CV]R There is one register (MDCCINT_EL1) which guest debug doesn't care about so this behaves as before. Signed-off-by: Alex Bennée <[email protected]> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 2c359c9..3d32d45 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -122,10 +122,13 @@ struct kvm_vcpu_arch { * here. */ - /* Registers pre any guest debug manipulations */ + /* Registers before any guest debug manipulations. These + * shadow registers are updated by the kvm_handle_sys_reg + * trap handler if the guest accesses or updates them + */ struct { u32 pstate_ss_bit; - u32 mdscr_el1_bits; + u32 mdscr_el1; struct kvm_guest_debug_arch debug_regs; } debug_saved_regs; diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 3b368f3..638c111 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -55,8 +55,6 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); - trace_kvm_arch_setup_debug_reg32("MDCR_EL2", vcpu->arch.mdcr_el2); - /* * If we are not treating debug registers are dirty we need * to trap if the guest starts accessing them. @@ -71,8 +69,10 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) /* Save pstate/mdscr */ vcpu_debug_saved_reg(vcpu, pstate_ss_bit) = *vcpu_cpsr(vcpu) & DBG_SPSR_SS; - vcpu_debug_saved_reg(vcpu, mdscr_el1_bits) = - vcpu_sys_reg(vcpu, MDSCR_EL1) & MDSCR_EL1_DEBUG_BITS; + + vcpu_debug_saved_reg(vcpu, mdscr_el1) = + vcpu_sys_reg(vcpu, MDSCR_EL1); + /* * Single Step (ARM ARM D2.12.3 The software step state * machine) @@ -161,9 +161,8 @@ void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; *vcpu_cpsr(vcpu) |= vcpu_debug_saved_reg(vcpu, pstate_ss_bit); - vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~MDSCR_EL1_DEBUG_BITS; - vcpu_sys_reg(vcpu, MDSCR_EL1) |= - vcpu_debug_saved_reg(vcpu, mdscr_el1_bits); + vcpu_sys_reg(vcpu, MDSCR_EL1) = + vcpu_debug_saved_reg(vcpu, mdscr_el1); /* * If we were using HW debug we need to restore the diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index be9b188..d43d7d1 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -208,39 +208,61 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu, const struct sys_reg_params *p, const struct sys_reg_desc *r) { - if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) { - struct kvm_guest_debug_arch *saved; - __u64 *val; - - saved = &vcpu_debug_saved_reg(vcpu, debug_regs); - - if (r->reg >= DBGBCR0_EL1 && r->reg <= DBGBCR15_EL1) - val = &saved->dbg_bcr[r->reg - DBGBCR0_EL1]; - else if (r->reg >= DBGBVR0_EL1 && r->reg <= DBGBVR15_EL1) - val = &saved->dbg_bvr[r->reg - DBGBVR0_EL1]; - else if (r->reg >= DBGWCR0_EL1 && r->reg <= DBGWCR15_EL1) - val = &saved->dbg_wcr[r->reg - DBGWCR0_EL1]; - else if (r->reg >= DBGWVR0_EL1 && r->reg <= DBGWVR15_EL1) - val = &saved->dbg_wvr[r->reg - DBGWVR0_EL1]; - else { - kvm_err("Bad register index %d\n", r->reg); - return false; + if (vcpu->guest_debug) { + + /* MDSCR_EL1 */ + if (r->reg == MDSCR_EL1) { + if (p->is_write) + vcpu_debug_saved_reg(vcpu, mdscr_el1) = + *vcpu_reg(vcpu, p->Rt); + else + *vcpu_reg(vcpu, p->Rt) = + vcpu_debug_saved_reg(vcpu, mdscr_el1); + + return true; } - if (p->is_write) - *val = *vcpu_reg(vcpu, p->Rt); - else - *vcpu_reg(vcpu, p->Rt) = *val; + /* MDCCINT_EL1 */ + if (r->reg == MDCCINT_EL1) + goto old; + + /* We only shadow DBG* if guest being debugged */ + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) { + struct kvm_guest_debug_arch *saved; + __u64 *val; + + saved = &vcpu_debug_saved_reg(vcpu, debug_regs); + + if (r->reg >= DBGBCR0_EL1 && r->reg <= DBGBCR15_EL1) + val = &saved->dbg_bcr[r->reg - DBGBCR0_EL1]; + else if (r->reg >= DBGBVR0_EL1 && r->reg <= DBGBVR15_EL1) + val = &saved->dbg_bvr[r->reg - DBGBVR0_EL1]; + else if (r->reg >= DBGWCR0_EL1 && r->reg <= DBGWCR15_EL1) + val = &saved->dbg_wcr[r->reg - DBGWCR0_EL1]; + else if (r->reg >= DBGWVR0_EL1 && r->reg <= DBGWVR15_EL1) + val = &saved->dbg_wvr[r->reg - DBGWVR0_EL1]; + else { + kvm_err("Bad register index %d\n", r->reg); + return false; + } - } else { - if (p->is_write) { - vcpu_sys_reg(vcpu, r->reg) = *vcpu_reg(vcpu, p->Rt); - vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY; - } else { - *vcpu_reg(vcpu, p->Rt) = vcpu_sys_reg(vcpu, r->reg); + if (p->is_write) + *val = *vcpu_reg(vcpu, p->Rt); + else + *vcpu_reg(vcpu, p->Rt) = *val; + + return true; } } +old: + if (p->is_write) { + vcpu_sys_reg(vcpu, r->reg) = *vcpu_reg(vcpu, p->Rt); + vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY; + } else { + *vcpu_reg(vcpu, p->Rt) = vcpu_sys_reg(vcpu, r->reg); + } + return true; } -- 2.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
