[PATCH v7 5/5] platform/x86/amd/hsmp: Enable protocol version 7 metric tables on the ACPI driver

The ACPI driver currently prepares the per-socket metric table only
on HSMP_PROTO_VER6. With protocol version 7 in use on Family 1Ah
Model 50h-5Fh, userspace cannot reach the larger ~13 KB table:
hsmp_get_tbl_dram_base() is skipped, sock->metric_tbl_addr stays
NULL, and the ioctl added earlier in this series has nothing to read.

Widen the proto_ver gate in init_acpi() from '== HSMP_PROTO_VER6'
to '>= HSMP_PROTO_VER6' so the DRAM region is mapped and
sock->metric_tbl_size is populated on protocol version 7 (and any
future compatible version), making the ioctl path functional.

hsmp_metric_tbl_acpi_read() now returns -EOPNOTSUPP whenever the
running protocol version is not VER6, because the sysfs binary
attribute cannot carry a table larger than PAGE_SIZE. Version 7
userspace gets a clear, actionable error and a documented pointer to
HSMP_IOCTL_GET_TELEMETRY_DATA; version 6 userspace sees no change.

The non-ACPI plat.c path is intentionally left untouched: it covers
Family 1Ah Model 0h-Fh hardware fixed at protocol version 6, where
the existing metrics_bin remains the supported interface.

Co-developed-by: Muthusamy Ramalingam <[email protected]>
Signed-off-by: Muthusamy Ramalingam <[email protected]>
Signed-off-by: Muralidhara M K <[email protected]>
---
 drivers/platform/x86/amd/hsmp/acpi.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/amd/hsmp/acpi.c b/drivers/platform/x86/amd/hsmp/acpi.c
index 24f54dc7254f..8257cd1da48e 100644
--- a/drivers/platform/x86/amd/hsmp/acpi.c
+++ b/drivers/platform/x86/amd/hsmp/acpi.c
@@ -277,13 +277,31 @@ static ssize_t hsmp_metric_tbl_acpi_read(struct file *filp, struct kobject *kobj
 	struct device *dev = container_of(kobj, struct device, kobj);
 	struct hsmp_socket *sock = dev_get_drvdata(dev);
 
+	/*
+	 * metrics_bin is a sysfs binary attribute and is capped at PAGE_SIZE.
+	 * It can therefore only carry the protocol version 6 metric table
+	 * (struct hsmp_metric_table).  The larger tables defined from protocol
+	 * version 7 onwards do not fit; userspace on those systems must read
+	 * the snapshot through HSMP_IOCTL_GET_TELEMETRY_DATA on /dev/hsmp.
+	 * Surface the unsupported case here as -EOPNOTSUPP rather than
+	 * silently truncating the snapshot.
+	 */
+	if (hsmp_pdev->proto_ver != HSMP_PROTO_VER6)
+		return -EOPNOTSUPP;
+
 	return hsmp_metric_tbl_read(sock, buf, count);
 }
 
 static umode_t hsmp_is_sock_attr_visible(struct kobject *kobj,
 					 const struct bin_attribute *battr, int id)
 {
-	if (hsmp_pdev->proto_ver == HSMP_PROTO_VER6)
+	/*
+	 * Keep metrics_bin visible on protocol version 7 and later as well,
+	 * so that userspace which expects the file to exist gets a clear
+	 * -EOPNOTSUPP from the read handler instead of -ENOENT, and is
+	 * pointed at HSMP_IOCTL_GET_TELEMETRY_DATA as the supported path.
+	 */
+	if (hsmp_pdev->proto_ver >= HSMP_PROTO_VER6)
 		return battr->attr.mode;
 
 	return 0;
@@ -539,7 +557,7 @@ static int init_acpi(struct device *dev)
 		return ret;
 	}
 
-	if (hsmp_pdev->proto_ver == HSMP_PROTO_VER6) {
+	if (hsmp_pdev->proto_ver >= HSMP_PROTO_VER6) {
 		ret = hsmp_get_tbl_dram_base(sock_ind);
 		if (ret)
 			dev_info(dev, "Failed to init metric table\n");
-- 
2.34.1