[PATCH v9 04/11] xen/memory: Add a vmtrace_buf resource type

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

From: Michał Leszczyński <michal.leszczynski@xxxxxxx>

Allow to map processor trace buffer using acquire_resource().

Signed-off-by: Michał Leszczyński <michal.leszczynski@xxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Michał Leszczyński <michal.leszczynski@xxxxxxx>
CC: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>

v8:
 * Rebase over 'fault' and ARM/IOREQ series.

v7:
 * Rebase over changes elsewhere in the series
---
 xen/common/memory.c         | 29 +++++++++++++++++++++++++++++
 xen/include/public/memory.h |  1 +
 2 files changed, 30 insertions(+)

diff --git a/xen/common/memory.c b/xen/common/memory.c
index 128718b31c..fada97a79f 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -1085,6 +1085,9 @@ static unsigned int resource_max_frames(const struct 
domain *d,
     case XENMEM_resource_ioreq_server:
         return ioreq_server_max_frames(d);
 
+    case XENMEM_resource_vmtrace_buf:
+        return d->vmtrace_size >> PAGE_SHIFT;
+
     default:
         return -EOPNOTSUPP;
     }
@@ -1125,6 +1128,29 @@ static int acquire_ioreq_server(struct domain *d,
 #endif
 }
 
+static int acquire_vmtrace_buf(
+    struct domain *d, unsigned int id, unsigned int frame,
+    unsigned int nr_frames, xen_pfn_t mfn_list[])
+{
+    const struct vcpu *v = domain_vcpu(d, id);
+    unsigned int i;
+    mfn_t mfn;
+
+    if ( !v )
+        return -ENOENT;
+
+    if ( !v->vmtrace.pg ||
+         (frame + nr_frames) > (d->vmtrace_size >> PAGE_SHIFT) )
+        return -EINVAL;
+
+    mfn = page_to_mfn(v->vmtrace.pg);
+
+    for ( i = 0; i < nr_frames; i++ )
+        mfn_list[i] = mfn_x(mfn) + frame + i;
+
+    return nr_frames;
+}
+
 /*
  * Returns -errno on error, or positive in the range [1, nr_frames] on
  * success.  Returning less than nr_frames contitutes a request for a
@@ -1142,6 +1168,9 @@ static int _acquire_resource(
     case XENMEM_resource_ioreq_server:
         return acquire_ioreq_server(d, id, frame, nr_frames, mfn_list);
 
+    case XENMEM_resource_vmtrace_buf:
+        return acquire_vmtrace_buf(d, id, frame, nr_frames, mfn_list);
+
     default:
         return -EOPNOTSUPP;
     }
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index 020c79d757..50e73eef98 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -625,6 +625,7 @@ 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
-- 
2.11.0