[PATCH v7 04/10] xen/memory: Add a vmtrace_buf resource type

[Andrew Cooper <andrew.cooper3@citrix.com>]

From: Michał Leszczyński <michal.leszczynski@cert.pl>

Allow to map processor trace buffer using acquire_resource().

Signed-off-by: Michał Leszczyński <michal.leszczynski@cert.pl>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Wei Liu <wl@xen.org>
CC: Michał Leszczyński <michal.leszczynski@cert.pl>
CC: Tamas K Lengyel <tamas@tklengyel.com>

v7:
 * Rebase over changes elsewhere in the series
---
 xen/common/memory.c         | 27 +++++++++++++++++++++++++++
 xen/include/public/memory.h |  1 +
 2 files changed, 28 insertions(+)

diff --git a/xen/common/memory.c b/xen/common/memory.c
index c89923d909..ec6a55172a 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -1068,11 +1068,35 @@ static unsigned int resource_max_frames(const struct domain *d,
     case XENMEM_resource_grant_table:
         return gnttab_resource_max_frames(d, id);
 
+    case XENMEM_resource_vmtrace_buf:
+        return d->vmtrace_frames;
+
     default:
         return arch_resource_max_frames(d, type, id);
     }
 }
 
+static int acquire_vmtrace_buf(
+    struct domain *d, unsigned int id, unsigned long 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 || !v->vmtrace.buf ||
+         nr_frames > d->vmtrace_frames ||
+         (frame + nr_frames) > d->vmtrace_frames )
+        return -EINVAL;
+
+    mfn = page_to_mfn(v->vmtrace.buf);
+
+    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
@@ -1087,6 +1111,9 @@ static int _acquire_resource(
     case XENMEM_resource_grant_table:
         return gnttab_acquire_resource(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 arch_acquire_resource(d, type, id, frame, nr_frames, mfn_list);
     }
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index c4c47a0b38..b0378bb14b 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