LinuxLists.cc - [PATCH v2] KVM: x86: Add tracepoint for dr_write/dr

2020-10-09 06:06:23

Subject: [PATCH v2] KVM: x86: Add tracepoint for dr_write/dr_read

From: Haiwei Li <[email protected]>

When vmexit occurs caused by accessing dr, there is no tracepoint to track
this action. Add tracepoint for this on x86 kvm.

Signed-off-by: Haiwei Li <[email protected]>
---
v1 -> v2:
* Improve the changelog

arch/x86/kvm/svm/svm.c | 2 ++
arch/x86/kvm/trace.h | 27 +++++++++++++++++++++++++++
arch/x86/kvm/vmx/vmx.c | 10 ++++++++--
arch/x86/kvm/x86.c | 1 +
4 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4f401fc6a05d..52c69551aea4 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2423,12 +2423,14 @@ static int dr_interception(struct vcpu_svm *svm)
if (!kvm_require_dr(&svm->vcpu, dr - 16))
return 1;
val = kvm_register_read(&svm->vcpu, reg);
+ trace_kvm_dr_write(dr - 16, val);
kvm_set_dr(&svm->vcpu, dr - 16, val);
} else {
if (!kvm_require_dr(&svm->vcpu, dr))
return 1;
kvm_get_dr(&svm->vcpu, dr, &val);
kvm_register_write(&svm->vcpu, reg, val);
+ trace_kvm_dr_read(dr, val);
}

return kvm_skip_emulated_instruction(&svm->vcpu);
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index aef960f90f26..b3bf54405862 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -405,6 +405,33 @@ TRACE_EVENT(kvm_cr,
#define trace_kvm_cr_read(cr, val) trace_kvm_cr(0, cr, val)
#define trace_kvm_cr_write(cr, val) trace_kvm_cr(1, cr, val)

+/*
+ * Tracepoint for guest DR access.
+ */
+TRACE_EVENT(kvm_dr,
+ TP_PROTO(unsigned int rw, unsigned int dr, unsigned long val),
+ TP_ARGS(rw, dr, val),
+
+ TP_STRUCT__entry(
+ __field( unsigned int, rw )
+ __field( unsigned int, dr )
+ __field( unsigned long, val )
+ ),
+
+ TP_fast_assign(
+ __entry->rw = rw;
+ __entry->dr = dr;
+ __entry->val = val;
+ ),
+
+ TP_printk("dr_%s %x = 0x%lx",
+ __entry->rw ? "write" : "read",
+ __entry->dr, __entry->val)
+);
+
+#define trace_kvm_dr_read(dr, val) trace_kvm_dr(0, dr, val)
+#define trace_kvm_dr_write(dr, val) trace_kvm_dr(1, dr, val)
+
TRACE_EVENT(kvm_pic_set_irq,
TP_PROTO(__u8 chip, __u8 pin, __u8 elcr, __u8 imr, bool coalesced),
TP_ARGS(chip, pin, elcr, imr, coalesced),
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4551a7e80ebc..f78fd297d51e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5091,10 +5091,16 @@ static int handle_dr(struct kvm_vcpu *vcpu)

if (kvm_get_dr(vcpu, dr, &val))
return 1;
+ trace_kvm_dr_read(dr, val);
kvm_register_write(vcpu, reg, val);
- } else
- if (kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg)))
+ } else {
+ unsigned long val;
+
+ val = kvm_register_readl(vcpu, reg);
+ trace_kvm_dr_write(dr, val);
+ if (kvm_set_dr(vcpu, dr, val))
return 1;
+ }

return kvm_skip_emulated_instruction(vcpu);
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c4015a43cc8a..68cb7b331324 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11153,6 +11153,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_msr);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_cr);
+EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_dr);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmrun);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit_inject);
--
2.18.4

2020-10-22 07:52:57

by Haiwei Li

[permalink] [raw]

Subject: Re: [PATCH v2] KVM: x86: Add tracepoint for dr_write/dr_read

Kindly ping. :)

On 20/10/9 11:21, [email protected] wrote:
> From: Haiwei Li <[email protected]>
>
> When vmexit occurs caused by accessing dr, there is no tracepoint to track
> this action. Add tracepoint for this on x86 kvm.
>
> Signed-off-by: Haiwei Li <[email protected]>
> ---
> v1 -> v2:
> * Improve the changelog
>
> arch/x86/kvm/svm/svm.c | 2 ++
> arch/x86/kvm/trace.h | 27 +++++++++++++++++++++++++++
> arch/x86/kvm/vmx/vmx.c | 10 ++++++++--
> arch/x86/kvm/x86.c | 1 +
> 4 files changed, 38 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 4f401fc6a05d..52c69551aea4 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -2423,12 +2423,14 @@ static int dr_interception(struct vcpu_svm *svm)
> if (!kvm_require_dr(&svm->vcpu, dr - 16))
> return 1;
> val = kvm_register_read(&svm->vcpu, reg);
> + trace_kvm_dr_write(dr - 16, val);
> kvm_set_dr(&svm->vcpu, dr - 16, val);
> } else {
> if (!kvm_require_dr(&svm->vcpu, dr))
> return 1;
> kvm_get_dr(&svm->vcpu, dr, &val);
> kvm_register_write(&svm->vcpu, reg, val);
> + trace_kvm_dr_read(dr, val);
> }
>
> return kvm_skip_emulated_instruction(&svm->vcpu);
> diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
> index aef960f90f26..b3bf54405862 100644
> --- a/arch/x86/kvm/trace.h
> +++ b/arch/x86/kvm/trace.h
> @@ -405,6 +405,33 @@ TRACE_EVENT(kvm_cr,
> #define trace_kvm_cr_read(cr, val) trace_kvm_cr(0, cr, val)
> #define trace_kvm_cr_write(cr, val) trace_kvm_cr(1, cr, val)
>
> +/*
> + * Tracepoint for guest DR access.
> + */
> +TRACE_EVENT(kvm_dr,
> + TP_PROTO(unsigned int rw, unsigned int dr, unsigned long val),
> + TP_ARGS(rw, dr, val),
> +
> + TP_STRUCT__entry(
> + __field( unsigned int, rw )
> + __field( unsigned int, dr )
> + __field( unsigned long, val )
> + ),
> +
> + TP_fast_assign(
> + __entry->rw = rw;
> + __entry->dr = dr;
> + __entry->val = val;
> + ),
> +
> + TP_printk("dr_%s %x = 0x%lx",
> + __entry->rw ? "write" : "read",
> + __entry->dr, __entry->val)
> +);
> +
> +#define trace_kvm_dr_read(dr, val) trace_kvm_dr(0, dr, val)
> +#define trace_kvm_dr_write(dr, val) trace_kvm_dr(1, dr, val)
> +
> TRACE_EVENT(kvm_pic_set_irq,
> TP_PROTO(__u8 chip, __u8 pin, __u8 elcr, __u8 imr, bool coalesced),
> TP_ARGS(chip, pin, elcr, imr, coalesced),
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 4551a7e80ebc..f78fd297d51e 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -5091,10 +5091,16 @@ static int handle_dr(struct kvm_vcpu *vcpu)
>
> if (kvm_get_dr(vcpu, dr, &val))
> return 1;
> + trace_kvm_dr_read(dr, val);
> kvm_register_write(vcpu, reg, val);
> - } else
> - if (kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg)))
> + } else {
> + unsigned long val;
> +
> + val = kvm_register_readl(vcpu, reg);
> + trace_kvm_dr_write(dr, val);
> + if (kvm_set_dr(vcpu, dr, val))
> return 1;
> + }
>
> return kvm_skip_emulated_instruction(vcpu);
> }
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c4015a43cc8a..68cb7b331324 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -11153,6 +11153,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_msr);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_cr);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_dr);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmrun);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit_inject);
>

2020-11-06 00:33:51

by Haiwei Li

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