[PATCH v4 05/10] xen/domain: Add DOMCTL handler for claiming memory with NUMA awareness

[Bernhard Kaindl <bernhard.kaindl@xxxxxxxxxx>]

Add a DOMCTL handler for claiming memory with NUMA awareness. It
rejects claims when LLC coloring (does not support claims) is enabled
and translates the public constant to the internal NUMA_NO_NODE.

The request is forwarded to domain_set_outstanding_pages() for the
actual claim processing. The handler uses the same XSM hook as the
legacy XENMEM_claim_pages hypercall.

While the underlying infrastructure currently supports only a single
claim, the public hypercall interface is designed to be extensible for
multiple claims in the future without breaking the API.

Signed-off-by: Bernhard Kaindl <bernhard.kaindl@xxxxxxxxxx>
---
 xen/common/domain.c         | 29 ++++++++++++++++++++++++++++
 xen/common/domctl.c         |  9 +++++++++
 xen/include/public/domctl.h | 38 +++++++++++++++++++++++++++++++++++++
 xen/include/xen/domain.h    |  2 ++
 4 files changed, 78 insertions(+)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index e7861259a2b3..ac1b091f5574 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -268,6 +268,35 @@ int get_domain_state(struct xen_domctl_get_domain_state 
*info, struct domain *d,
     return rc;
 }
 
+/* Claim memory for a domain or reset the claim */
+int claim_memory(struct domain *d, const struct xen_domctl_claim_memory *uinfo)
+{
+    memory_claim_t claim;
+
+    /* alloc_color_heap_page() does not handle claims, so reject LLC coloring 
*/
+    if ( llc_coloring_enabled )
+        return -EOPNOTSUPP;
+    /*
+     * We only support single claims at the moment, and if the domain is
+     * dying (d->is_dying is set), its claims have already been released
+     */
+    if ( uinfo->pad || uinfo->nr_claims != 1 || d->is_dying )
+        return -EINVAL;
+
+    if ( copy_from_guest(&claim, uinfo->claims, 1) )
+        return -EFAULT;
+
+    if ( claim.pad )
+        return -EINVAL;
+
+    /* Convert the API tag for a host-wide claim to the NUMA_NO_NODE constant 
*/
+    if ( claim.node == XEN_DOMCTL_CLAIM_MEMORY_NO_NODE )
+        claim.node = NUMA_NO_NODE;
+
+    /* NB. domain_set_outstanding_pages() has the checks to validate its args 
*/
+    return domain_set_outstanding_pages(d, claim.pages, claim.node);
+}
+
 static void __domain_finalise_shutdown(struct domain *d)
 {
     struct vcpu *v;
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 29a7726d32d0..9e858f631aaf 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -868,6 +868,15 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
         ret = get_domain_state(&op->u.get_domain_state, d, &op->domain);
         break;
 
+    case XEN_DOMCTL_claim_memory:
+        /* Use the same XSM hook as XENMEM_claim_pages */
+        ret = xsm_claim_pages(XSM_PRIV, d);
+        if ( ret )
+            break;
+
+        ret = claim_memory(d, &op->u.claim_memory);
+        break;
+
     default:
         ret = arch_do_domctl(op, d, u_domctl);
         break;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 8f6708c0a7cd..610806c8b6e0 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -1276,6 +1276,42 @@ struct xen_domctl_get_domain_state {
     uint64_t unique_id;      /* Unique domain identifier. */
 };
 
+/*
+ * XEN_DOMCTL_claim_memory
+ *
+ * Claim memory for a guest domain. The claimed memory is converted into actual
+ * memory pages by allocating it. Except for the option to pass claims for
+ * multiple NUMA nodes, the semantics are based on host-wide claims as
+ * provided by XENMEM_claim_pages, and are identical for host-wide claims.
+ *
+ * The initial implementation supports a claim for the host or a NUMA node, but
+ * using an array, the API is designed to be extensible to support more claims.
+ */
+struct xen_memory_claim {
+    uint64_aligned_t pages;   /* Amount of pages to be allotted to the domain 
*/
+    uint32_t node;  /* NUMA node, or XEN_DOMCTL_CLAIM_MEMORY_NO_NODE for host 
*/
+    uint32_t pad;                 /* padding for alignment, set to 0 on input 
*/
+};
+typedef struct xen_memory_claim memory_claim_t;
+#define XEN_DOMCTL_CLAIM_MEMORY_NO_NODE    0xFFFFFFFF  /* No node: host claim 
*/
+
+/* Use XEN_NODE_CLAIM_INIT to initialize a memory_claim_t structure */
+#define XEN_NODE_CLAIM_INIT(_pages, _node) { \
+    .pages = (_pages),                  \
+    .node = (_node),                    \
+    .pad = 0                            \
+}
+DEFINE_XEN_GUEST_HANDLE(memory_claim_t);
+
+struct xen_domctl_claim_memory {
+    /* IN: array of struct xen_memory_claim */
+    XEN_GUEST_HANDLE_64(memory_claim_t) claims;
+    /* IN: number of claims in the claims array handle. See the claims field. 
*/
+    uint32_t nr_claims;
+#define XEN_DOMCTL_MAX_CLAIMS UINT8_MAX /* More claims require changes in Xen 
*/
+    uint32_t pad;                       /* padding for alignment, set it to 0 
*/
+};
+
 struct xen_domctl {
 /* Stable domctl ops: interface_version is required to be 0.  */
     uint32_t cmd;
@@ -1368,6 +1404,7 @@ struct xen_domctl {
 #define XEN_DOMCTL_gsi_permission                88
 #define XEN_DOMCTL_set_llc_colors                89
 #define XEN_DOMCTL_get_domain_state              90 /* stable interface */
+#define XEN_DOMCTL_claim_memory                  91
 #define XEN_DOMCTL_gdbsx_guestmemio            1000
 #define XEN_DOMCTL_gdbsx_pausevcpu             1001
 #define XEN_DOMCTL_gdbsx_unpausevcpu           1002
@@ -1436,6 +1473,7 @@ struct xen_domctl {
 #endif
         struct xen_domctl_set_llc_colors    set_llc_colors;
         struct xen_domctl_get_domain_state  get_domain_state;
+        struct xen_domctl_claim_memory      claim_memory;
         uint8_t                             pad[128];
     } u;
 };
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 93c0fd00c1d7..79e8932c4530 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -193,4 +193,6 @@ extern bool vmtrace_available;
 
 extern bool vpmu_is_available;
 
+int claim_memory(struct domain *d, const struct xen_domctl_claim_memory 
*uinfo);
+
 #endif /* __XEN_DOMAIN_H__ */
-- 
2.39.5