[xen staging] xen/memory: Add a vmtrace_buf resource type

[patchbot@xxxxxxx]

commit b72eab263592a3d76aa826675e5d62606d83cecd
Author:     MichaÅ? LeszczyÅ?ski <michal.leszczynski@xxxxxxx>
AuthorDate: Mon Jun 29 00:05:51 2020 +0200
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Fri Feb 5 17:37:27 2021 +0000

    xen/memory: Add a vmtrace_buf resource type
    
    Allow to map processor trace buffer using acquire_resource().
    
    Signed-off-by: MichaÅ? LeszczyÅ?ski <michal.leszczynski@xxxxxxx>
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Release-Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
---
 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 7b012ce291..76b9f58478 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -1096,6 +1096,9 @@ 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;
     }
@@ -1136,6 +1139,29 @@ 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
@@ -1153,6 +1179,9 @@ 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
--
generated by git-patchbot for /home/xen/git/xen.git#staging