[PATCH v6 29/64] KVM: arm64: nv: Forward debug traps to the nested guest

Marc Zyngier
2022-01-28T12:43:37Z

On handling a debug trap, check whether we need to forward it to the
guest before handling it.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/kvm_nested.h | 2 ++
arch/arm64/kvm/emulate-nested.c | 9 +++++++--
arch/arm64/kvm/sys_regs.c | 3 +++
3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 82fc8b6c990b..047ca700163b 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -66,6 +66,8 @@ static inline u64 translate_cnthctl_el2_to_cntkctl_el1(u64 cnthctl)
}

int handle_wfx_nested(struct kvm_vcpu *vcpu, bool is_wfe);
+extern bool __forward_traps(struct kvm_vcpu *vcpu, unsigned int reg,
+ u64 control_bit);
extern bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit);
extern bool forward_nv_traps(struct kvm_vcpu *vcpu);
extern bool forward_nv1_traps(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 0109dfd664dd..1f6cf8fe9fe3 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -13,14 +13,14 @@

#include "trace.h"

-bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)
+bool __forward_traps(struct kvm_vcpu *vcpu, unsigned int reg, u64 control_bit)
{
bool control_bit_set;

if (!vcpu_has_nv(vcpu))
return false;

- control_bit_set = __vcpu_sys_reg(vcpu, HCR_EL2) & control_bit;
+ control_bit_set = __vcpu_sys_reg(vcpu, reg) & control_bit;
if (!vcpu_is_el2(vcpu) && control_bit_set) {
kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
return true;
@@ -28,6 +28,11 @@ bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)
return false;
}

+bool forward_traps(struct kvm_vcpu *vcpu, u64 control_bit)
+{
+ return __forward_traps(vcpu, HCR_EL2, control_bit);
+}
+
bool forward_nv_traps(struct kvm_vcpu *vcpu)
{
return forward_traps(vcpu, HCR_NV);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 697bf0bca550..3e1f37c507a8 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -566,6 +566,9 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
+ if (__forward_traps(vcpu, MDCR_EL2, MDCR_EL2_TDA | MDCR_EL2_TDE))
+ return false;
+
access_rw(vcpu, p, r);
if (p->is_write)
vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;