[PATCH v4 10/16] powerpc/pseries/vas: Implement getting capabilities from hypervisor

[Haren Myneni]

The hypervisor provides VAS capabilities for GZIP default and QoS
features. These capabilities gives information for the specific
features such as total number of credits available in LPAR,
maximum credits allowed per window, maximum credits allowed in
LPAR, whether usermode copy/paste is supported, and etc.

This patch adds the following:
- Retrieve all features that are provided by hypervisor using
  H_QUERY_VAS_CAPABILITIES hcall with 0 as feature type.
- Retrieve capabilities for the specific feature using the same
  hcall and the feature type (1 for QoS and 2 for default type).

Signed-off-by: Haren Myneni <haren at linux.ibm.com>
---
 arch/powerpc/platforms/pseries/vas.c | 127 +++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index 06960151477c..9976f6b614b9 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -30,6 +30,13 @@
 /* phyp allows one credit per window right now */
 #define DEF_WIN_CREDS		1
 
+static struct vas_all_caps caps_all;
+static bool copypaste_feat;
+
+static struct vas_caps vascaps[VAS_MAX_FEAT_TYPE];
+
+static DEFINE_MUTEX(vas_pseries_mutex);
+
 static int64_t hcall_return_busy_check(int64_t rc)
 {
 	/* Check if we are stalled for some time */
@@ -215,3 +222,123 @@ int plpar_vas_query_capabilities(const u64 hcall, u8 query_type,
 		return -EIO;
 	}
 }
+
+/*
+ * Get the specific capabilities based on the feature type.
+ * Right now supports GZIP default and GZIP QoS capabilities.
+ */
+static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
+				struct hv_vas_ct_caps *hv_caps)
+{
+	struct vas_ct_caps *caps;
+	struct vas_caps *vcaps;
+	int rc = 0;
+
+	vcaps = &vascaps[type];
+	memset(vcaps, 0, sizeof(*vcaps));
+	INIT_LIST_HEAD(&vcaps->list);
+
+	caps = &vcaps->caps;
+
+	rc = plpar_vas_query_capabilities(H_QUERY_VAS_CAPABILITIES, feat,
+					  (u64)virt_to_phys(hv_caps));
+	if (rc)
+		return rc;
+
+	caps->user_mode = hv_caps->user_mode;
+	if (!(caps->user_mode & VAS_COPY_PASTE_USER_MODE)) {
+		pr_err("User space COPY/PASTE is not supported\n");
+		return -ENOTSUPP;
+	}
+
+	snprintf(caps->name, VAS_DESCR_LEN + 1, "%.8s",
+		 (char *)&hv_caps->descriptor);
+	caps->descriptor = be64_to_cpu(hv_caps->descriptor);
+	caps->win_type = hv_caps->win_type;
+	if (caps->win_type >= VAS_MAX_FEAT_TYPE) {
+		pr_err("Unsupported window type %u\n", caps->win_type);
+		return -EINVAL;
+	}
+	caps->max_lpar_creds = be16_to_cpu(hv_caps->max_lpar_creds);
+	caps->max_win_creds = be16_to_cpu(hv_caps->max_win_creds);
+	atomic_set(&caps->target_lpar_creds,
+		   be16_to_cpu(hv_caps->target_lpar_creds));
+	if (feat == VAS_GZIP_DEF_FEAT) {
+		caps->def_lpar_creds = be16_to_cpu(hv_caps->def_lpar_creds);
+
+		if (caps->max_win_creds < DEF_WIN_CREDS) {
+			pr_err("Window creds(%u) > max allowed window creds(%u)\n",
+			       DEF_WIN_CREDS, caps->max_win_creds);
+			return -EINVAL;
+		}
+	}
+
+	copypaste_feat = true;
+
+	return 0;
+}
+
+static int __init pseries_vas_init(void)
+{
+	struct hv_vas_ct_caps *hv_ct_caps;
+	struct hv_vas_all_caps *hv_caps;
+	int rc;
+
+	/*
+	 * Linux supports user space COPY/PASTE only with Radix
+	 */
+	if (!radix_enabled()) {
+		pr_err("API is supported only with radix page tables\n");
+		return -ENOTSUPP;
+	}
+
+	hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL);
+	if (!hv_caps)
+		return -ENOMEM;
+	/*
+	 * Get VAS overall capabilities by passing 0 to feature type.
+	 */
+	rc = plpar_vas_query_capabilities(H_QUERY_VAS_CAPABILITIES, 0,
+					  (u64)virt_to_phys(hv_caps));
+	if (rc)
+		goto out;
+
+	snprintf(caps_all.name, VAS_DESCR_LEN, "%.7s",
+		 (char *)&hv_caps->descriptor);
+	caps_all.descriptor = be64_to_cpu(hv_caps->descriptor);
+	caps_all.feat_type = be64_to_cpu(hv_caps->feat_type);
+
+	hv_ct_caps = kmalloc(sizeof(*hv_ct_caps), GFP_KERNEL);
+	if (!hv_ct_caps) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	/*
+	 * QOS capabilities available
+	 */
+	if (caps_all.feat_type & VAS_GZIP_QOS_FEAT_BIT) {
+		rc = get_vas_capabilities(VAS_GZIP_QOS_FEAT,
+					  VAS_GZIP_QOS_FEAT_TYPE, hv_ct_caps);
+
+		if (rc)
+			goto out_ct;
+	}
+	/*
+	 * Default capabilities available
+	 */
+	if (caps_all.feat_type & VAS_GZIP_DEF_FEAT_BIT) {
+		rc = get_vas_capabilities(VAS_GZIP_DEF_FEAT,
+					  VAS_GZIP_DEF_FEAT_TYPE, hv_ct_caps);
+		if (rc)
+			goto out_ct;
+	}
+
+	pr_info("GZIP feature is available\n");
+
+out_ct:
+	kfree(hv_ct_caps);
+out:
+	kfree(hv_caps);
+	return rc;
+}
+machine_device_initcall(pseries, pseries_vas_init);
-- 
2.18.2