Re: [PATCH v4 07/10] x86/mm: add vmtrace_buf resource type

[Roger Pau Monné]

On Tue, Jun 30, 2020 at 02:33:50PM +0200, Michał Leszczyński wrote:
> From: Michal Leszczynski 
> 
> Allow to map processor trace buffer using
> acquire_resource().
> 
> Signed-off-by: Michal Leszczynski 
> ---
>  xen/arch/x86/mm.c   | 25 +
>  xen/include/public/memory.h |  1 +
>  2 files changed, 26 insertions(+)
> 
> diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
> index e376fc7e8f..bb781bd90c 100644
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -4624,6 +4624,31 @@ int arch_acquire_resource(struct domain *d, unsigned 
> int type,
>  }
>  break;
>  }
> +
> +case XENMEM_resource_vmtrace_buf:
> +{
> +mfn_t mfn;
> +unsigned int i;
> +struct vcpu *v = domain_vcpu(d, id);

Missing blank newline between variable definitions and code.

> +rc = -EINVAL;
> +
> +if ( !v )
> +break;
> +
> +if ( !v->arch.vmtrace.pt_buf )
> +break;
> +
> +mfn = page_to_mfn(v->arch.vmtrace.pt_buf);
> +
> +if ( frame + nr_frames > (v->domain->vmtrace_pt_size >> PAGE_SHIFT) )
> +break;

You can place all the checks done above in a single if.

Thanks, Roger.

[PATCH v4 07/10] x86/mm: add vmtrace_buf resource type

[Michał Leszczyński]

From: Michal Leszczynski 

Allow to map processor trace buffer using
acquire_resource().

Signed-off-by: Michal Leszczynski 
---
 xen/arch/x86/mm.c   | 25 +
 xen/include/public/memory.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index e376fc7e8f..bb781bd90c 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4624,6 +4624,31 @@ int arch_acquire_resource(struct domain *d, unsigned int 
type,
 }
 break;
 }
+
+case XENMEM_resource_vmtrace_buf:
+{
+mfn_t mfn;
+unsigned int i;
+struct vcpu *v = domain_vcpu(d, id);
+rc = -EINVAL;
+
+if ( !v )
+break;
+
+if ( !v->arch.vmtrace.pt_buf )
+break;
+
+mfn = page_to_mfn(v->arch.vmtrace.pt_buf);
+
+if ( frame + nr_frames > (v->domain->vmtrace_pt_size >> PAGE_SHIFT) )
+break;
+
+rc = 0;
+for ( i = 0; i < nr_frames; i++ )
+mfn_list[i] = mfn_x(mfn_add(mfn, frame + i));
+
+break;
+}
 #endif
 
 default:
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index dbd35305df..f823c784c3 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -620,6 +620,7 @@ struct xen_mem_acquire_resource {
 
 #define XENMEM_resource_ioreq_server 0
 #define XENMEM_resource_grant_table 1
+#define XENMEM_resource_vmtrace_buf 2
 
 /*
  * IN - a type-specific resource identifier, which must be zero
-- 
2.20.1