[PATCH v3 28/66] KVM: arm64: nv: Forward debug traps to the nested guest

Marc Zyngier
2020-12-10T16:32:57Z

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 26cba7b4d743..07c15f51cf86 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -62,6 +62,8 @@ 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);

diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index feb9b5eded96..df4661515183 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -25,14 +25,14 @@

#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 (!nested_virt_in_use(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_mode_el2(vcpu) && control_bit_set) {
kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
return true;
@@ -40,6 +40,11 @@ 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 dc8a33ebad5f..80cf0c0761b9 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -607,6 +607,9 @@ 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;
--
2.29.2