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Merge branch 'kvm-arm64/debug-5.13' into kvmarm-master/next

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Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2021-04-13 15:34:15 +01:00
commit fbb31e5f3a
6 changed files with 83 additions and 29 deletions
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3
Documentation/virt/kvm/api.rst
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@ -3334,7 +3334,8 @@ The top 16 bits of the control field are architecture specific control
flags which can include the following:
- KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64]
- KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390, arm64]
- KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390]
- KVM_GUESTDBG_USE_HW: using hardware debug events [arm64]
- KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86]
- KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86]
- KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390]

1
arch/arm64/include/asm/kvm_host.h
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@ -717,6 +717,7 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
void kvm_arm_init_debug(void);
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);

2
arch/arm64/include/asm/sysreg.h
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@ -283,6 +283,8 @@
#define SYS_PMSIRR_EL1_INTERVAL_MASK 0xffffffUL
/* Filtering controls */
#define SYS_PMSNEVFR_EL1 sys_reg(3, 0, 9, 9, 1)
#define SYS_PMSFCR_EL1 sys_reg(3, 0, 9, 9, 4)
#define SYS_PMSFCR_EL1_FE_SHIFT 0
#define SYS_PMSFCR_EL1_FT_SHIFT 1

2
arch/arm64/kvm/arm.c
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@ -582,6 +582,8 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
vcpu->arch.has_run_once = true;
kvm_arm_vcpu_init_debug(vcpu);
if (likely(irqchip_in_kernel(kvm))) {
/*
* Map the VGIC hardware resources before running a vcpu the

89
arch/arm64/kvm/debug.c
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@ -68,6 +68,65 @@ void kvm_arm_init_debug(void)
__this_cpu_write(mdcr_el2, kvm_call_hyp_ret(__kvm_get_mdcr_el2));
}
/**
* kvm_arm_setup_mdcr_el2 - configure vcpu mdcr_el2 value
*
* @vcpu: the vcpu pointer
*
* This ensures we will trap access to:
* - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR)
* - Debug ROM Address (MDCR_EL2_TDRA)
* - OS related registers (MDCR_EL2_TDOSA)
* - Statistical profiler (MDCR_EL2_TPMS/MDCR_EL2_E2PB)
* - Self-hosted Trace Filter controls (MDCR_EL2_TTRF)
* - Self-hosted Trace (MDCR_EL2_TTRF/MDCR_EL2_E2TB)
*/
static void kvm_arm_setup_mdcr_el2(struct kvm_vcpu *vcpu)
{
/*
* This also clears MDCR_EL2_E2PB_MASK and MDCR_EL2_E2TB_MASK
* to disable guest access to the profiling and trace buffers
*/
vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;
vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
MDCR_EL2_TPMS |
MDCR_EL2_TTRF |
MDCR_EL2_TPMCR |
MDCR_EL2_TDRA |
MDCR_EL2_TDOSA);
/* Is the VM being debugged by userspace? */
if (vcpu->guest_debug)
/* Route all software debug exceptions to EL2 */
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 (KVM_ARM64_DEBUG_DIRTY is clear).
*/
if ((vcpu->guest_debug & KVM_GUESTDBG_USE_HW) ||
!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
}
/**
* kvm_arm_vcpu_init_debug - setup vcpu debug traps
*
* @vcpu: the vcpu pointer
*
* Set vcpu initial mdcr_el2 value.
*/
void kvm_arm_vcpu_init_debug(struct kvm_vcpu *vcpu)
{
preempt_disable();
kvm_arm_setup_mdcr_el2(vcpu);
preempt_enable();
}
/**
* kvm_arm_reset_debug_ptr - reset the debug ptr to point to the vcpu state
*/
@ -83,13 +142,7 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
* @vcpu: the vcpu pointer
*
* This is called before each entry into the hypervisor to setup any
* debug related registers. Currently this just ensures we will trap
* access to:
* - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR)
* - Debug ROM Address (MDCR_EL2_TDRA)
* - OS related registers (MDCR_EL2_TDOSA)
* - Statistical profiler (MDCR_EL2_TPMS/MDCR_EL2_E2PB)
* - Self-hosted Trace (MDCR_EL2_TTRF/MDCR_EL2_E2TB)
* debug related registers.
*
* Additionally, KVM only traps guest accesses to the debug registers if
* the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY
@ -101,28 +154,14 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
{
bool trap_debug = !(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY);
unsigned long mdscr, orig_mdcr_el2 = vcpu->arch.mdcr_el2;
trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
/*
* This also clears MDCR_EL2_E2PB_MASK and MDCR_EL2_E2TB_MASK
* to disable guest access to the profiling and trace buffers
*/
vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;
vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
MDCR_EL2_TPMS |
MDCR_EL2_TTRF |
MDCR_EL2_TPMCR |
MDCR_EL2_TDRA |
MDCR_EL2_TDOSA);
kvm_arm_setup_mdcr_el2(vcpu);
/* Is Guest debugging in effect? */
if (vcpu->guest_debug) {
/* Route all software debug exceptions to EL2 */
vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE;
/* Save guest debug state */
save_guest_debug_regs(vcpu);
@ -176,7 +215,6 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state;
vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
trap_debug = true;
trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
&vcpu->arch.debug_ptr->dbg_bcr[0],
@ -191,10 +229,6 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
BUG_ON(!vcpu->guest_debug &&
vcpu->arch.debug_ptr != &vcpu->arch.vcpu_debug_state);
/* Trap debug register access */
if (trap_debug)
vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
/* 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->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
@ -203,7 +237,6 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
if (has_vhe() && orig_mdcr_el2 != vcpu->arch.mdcr_el2)
write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_read_sys_reg(vcpu, MDSCR_EL1));
}

15
arch/arm64/kvm/sys_regs.c
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@ -1063,6 +1063,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
val = cpuid_feature_cap_perfmon_field(val,
ID_AA64DFR0_PMUVER_SHIFT,
kvm_vcpu_has_pmu(vcpu) ? ID_AA64DFR0_PMUVER_8_4 : 0);
/* Hide SPE from guests */
val &= ~FEATURE(ID_AA64DFR0_PMSVER);
break;
case SYS_ID_DFR0_EL1:
/* Limit guests to PMUv3 for ARMv8.4 */
@ -1502,6 +1504,19 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_FAR_EL1), access_vm_reg, reset_unknown, FAR_EL1 },
{ SYS_DESC(SYS_PAR_EL1), NULL, reset_unknown, PAR_EL1 },
{ SYS_DESC(SYS_PMSCR_EL1), undef_access },
{ SYS_DESC(SYS_PMSNEVFR_EL1), undef_access },
{ SYS_DESC(SYS_PMSICR_EL1), undef_access },
{ SYS_DESC(SYS_PMSIRR_EL1), undef_access },
{ SYS_DESC(SYS_PMSFCR_EL1), undef_access },
{ SYS_DESC(SYS_PMSEVFR_EL1), undef_access },
{ SYS_DESC(SYS_PMSLATFR_EL1), undef_access },
{ SYS_DESC(SYS_PMSIDR_EL1), undef_access },
{ SYS_DESC(SYS_PMBLIMITR_EL1), undef_access },
{ SYS_DESC(SYS_PMBPTR_EL1), undef_access },
{ SYS_DESC(SYS_PMBSR_EL1), undef_access },
/* PMBIDR_EL1 is not trapped */
{ PMU_SYS_REG(SYS_PMINTENSET_EL1),
.access = access_pminten, .reg = PMINTENSET_EL1 },
{ PMU_SYS_REG(SYS_PMINTENCLR_EL1),