[PATCH v5] powerpc/pseries: read the lpar name from the firmware

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE1666d LANDED

Landed in mainline as eddaa9a40275 on 2022-02-02.

7 messages, 6 authors, 2022-02-15 · open the first message on its own page

[PATCH v5] powerpc/pseries: read the lpar name from the firmware

From: Laurent Dufour <hidden>
Date: 2022-01-06 16:13:53

The LPAR name may be changed after the LPAR has been started in the HMC.
In that case lparstat command is not reporting the updated value because it
reads it from the device tree which is read at boot time.

However this value could be read from RTAS.

Adding this value in the /proc/powerpc/lparcfg output allows to read the
updated value.

However the hypervisor, like Qemu/KVM, may not support this RTAS
parameter. In that case the value reported in lparcfg is read from the
device tree and so is not updated accordingly.

Cc: Nathan Lynch <redacted>
Signed-off-by: Laurent Dufour <redacted>
---
v5:
 fallback to the device tree value if RTAS is not providing the value.
v4:
 address Nathan's new comments limiting size of the buffer.
v3:
 address Michael's comments.
v2:
 address Nathan's comments.
 change title to partition_name aligning with existing partition_id
---
 arch/powerpc/platforms/pseries/lparcfg.c | 93 ++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
index c7940fcfc911..8ca08fc306e7 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c

@@ -311,6 +311,98 @@ static void parse_mpp_x_data(struct seq_file *m)
 		seq_printf(m, "coalesce_pool_spurr=%ld\n", mpp_x_data.pool_spurr_cycles);
 }
 
+/*
+ * PAPR defines, in section "7.3.16 System Parameters Option", the token 55 to
+ * read the LPAR name, and the largest output data to 4000 + 2 bytes length.
+ */
+#define SPLPAR_LPAR_NAME_TOKEN	55
+#define GET_SYS_PARM_BUF_SIZE	4002
+#if GET_SYS_PARM_BUF_SIZE > RTAS_DATA_BUF_SIZE
+#error "GET_SYS_PARM_BUF_SIZE is larger than RTAS_DATA_BUF_SIZE"
+#endif
+
+/**
+ * Read the lpar name using the RTAS ibm,get-system-parameter call.
+ *
+ * The name read through this call is updated if changes are made by the end
+ * user on the hypervisor side.
+ *
+ * Some hypervisor (like Qemu) may not provide this value. In that case, a non
+ * null value is returned.
+ */
+static int read_RTAS_lpar_name(struct seq_file *m)
+{
+	int rc, len, token;
+	union {
+		char raw_buffer[GET_SYS_PARM_BUF_SIZE];
+		struct {
+			__be16 len;
+			char name[GET_SYS_PARM_BUF_SIZE-2];
+		};
+	} *local_buffer;
+
+	token = rtas_token("ibm,get-system-parameter");
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -EINVAL;
+
+	local_buffer = kmalloc(sizeof(*local_buffer), GFP_KERNEL);
+	if (!local_buffer)
+		return -ENOMEM;
+
+	do {
+		spin_lock(&rtas_data_buf_lock);
+		memset(rtas_data_buf, 0, sizeof(*local_buffer));
+		rc = rtas_call(token, 3, 1, NULL, SPLPAR_LPAR_NAME_TOKEN,
+			       __pa(rtas_data_buf), sizeof(*local_buffer));
+		if (!rc)
+			memcpy(local_buffer->raw_buffer, rtas_data_buf,
+			       sizeof(local_buffer->raw_buffer));
+		spin_unlock(&rtas_data_buf_lock);
+	} while (rtas_busy_delay(rc));
+
+	if (!rc) {
+		/* Force end of string */
+		len = min((int) be16_to_cpu(local_buffer->len),
+			  (int) sizeof(local_buffer->name)-1);
+		local_buffer->name[len] = '\0';
+
+		seq_printf(m, "partition_name=%s\n", local_buffer->name);
+	} else
+		rc = -ENODATA;
+
+	kfree(local_buffer);
+	return rc;
+}
+
+/**
+ * Read the LPAR name from the Device Tree.
+ *
+ * The value read in the DT is not updated if the end-user is touching the LPAR
+ * name on the hypervisor side.
+ */
+static int read_DT_lpar_name(struct seq_file *m)
+{
+	struct device_node *rootdn;
+	const char *name;
+
+	rootdn = of_find_node_by_path("/");
+	if (!rootdn)
+		return -ENOENT;
+
+	name = of_get_property(rootdn, "ibm,partition-name", NULL);
+	if (!name)
+		return -ENOENT;
+
+	seq_printf(m, "partition_name=%s\n", name);
+	return 0;
+}
+
+static void read_lpar_name(struct seq_file *m)
+{
+	if (read_RTAS_lpar_name(m) && read_DT_lpar_name(m))
+		pr_err_once("Error can't get the LPAR name");
+}
+
 #define SPLPAR_CHARACTERISTICS_TOKEN 20
 #define SPLPAR_MAXLENGTH 1026*(sizeof(char))

@@ -496,6 +588,7 @@ static int pseries_lparcfg_data(struct seq_file *m, void *v)
 
 	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 		/* this call handles the ibm,get-system-parameter contents */
+		read_lpar_name(m);
 		parse_system_parameter_string(m);
 		parse_ppp_data(m);
 		parse_mpp_data(m);

-- 
2.34.1

Re: [PATCH v5] powerpc/pseries: read the lpar name from the firmware

From: Nathan Lynch <hidden>
Date: 2022-01-06 21:13:52

Laurent Dufour [off-list ref] writes:

The LPAR name may be changed after the LPAR has been started in the HMC.
In that case lparstat command is not reporting the updated value because it
reads it from the device tree which is read at boot time.

However this value could be read from RTAS.

Adding this value in the /proc/powerpc/lparcfg output allows to read the
updated value.

However the hypervisor, like Qemu/KVM, may not support this RTAS
parameter. In that case the value reported in lparcfg is read from the
device tree and so is not updated accordingly.

Cc: Nathan Lynch <redacted>
Signed-off-by: Laurent Dufour <redacted>
---
v5:
 fallback to the device tree value if RTAS is not providing the value.
v4:
 address Nathan's new comments limiting size of the buffer.
v3:
 address Michael's comments.
v2:
 address Nathan's comments.
 change title to partition_name aligning with existing partition_id

Thanks Laurent.

Reviewed-by: Nathan Lynch <redacted>

Re: [PATCH v5] powerpc/pseries: read the lpar name from the firmware

From: Tyrel Datwyler <tyreld@linux.ibm.com>
Date: 2022-01-06 21:38:12

On 1/6/22 8:13 AM, Laurent Dufour wrote:

The LPAR name may be changed after the LPAR has been started in the HMC.
In that case lparstat command is not reporting the updated value because it
reads it from the device tree which is read at boot time.

However this value could be read from RTAS.

Adding this value in the /proc/powerpc/lparcfg output allows to read the
updated value.

However the hypervisor, like Qemu/KVM, may not support this RTAS
parameter. In that case the value reported in lparcfg is read from the
device tree and so is not updated accordingly.

Cc: Nathan Lynch <redacted>
Signed-off-by: Laurent Dufour <redacted>

My only nit would be that in general for consistency with other function names
_RTAS_ and _DT_ should be lowercase. Seeing as they are statically scoped within
lparcfg.c maybe its ok. Otherwise,

Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>

quoted hunk

---
v5:
 fallback to the device tree value if RTAS is not providing the value.
v4:
 address Nathan's new comments limiting size of the buffer.
v3:
 address Michael's comments.
v2:
 address Nathan's comments.
 change title to partition_name aligning with existing partition_id
---
 arch/powerpc/platforms/pseries/lparcfg.c | 93 ++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
index c7940fcfc911..8ca08fc306e7 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c

@@ -311,6 +311,98 @@ static void parse_mpp_x_data(struct seq_file *m)
 		seq_printf(m, "coalesce_pool_spurr=%ld\n", mpp_x_data.pool_spurr_cycles);
 }
 
+/*
+ * PAPR defines, in section "7.3.16 System Parameters Option", the token 55 to
+ * read the LPAR name, and the largest output data to 4000 + 2 bytes length.
+ */
+#define SPLPAR_LPAR_NAME_TOKEN	55
+#define GET_SYS_PARM_BUF_SIZE	4002
+#if GET_SYS_PARM_BUF_SIZE > RTAS_DATA_BUF_SIZE
+#error "GET_SYS_PARM_BUF_SIZE is larger than RTAS_DATA_BUF_SIZE"
+#endif
+
+/**
+ * Read the lpar name using the RTAS ibm,get-system-parameter call.
+ *
+ * The name read through this call is updated if changes are made by the end
+ * user on the hypervisor side.
+ *
+ * Some hypervisor (like Qemu) may not provide this value. In that case, a non
+ * null value is returned.
+ */
+static int read_RTAS_lpar_name(struct seq_file *m)
+{
+	int rc, len, token;
+	union {
+		char raw_buffer[GET_SYS_PARM_BUF_SIZE];
+		struct {
+			__be16 len;
+			char name[GET_SYS_PARM_BUF_SIZE-2];
+		};
+	} *local_buffer;
+
+	token = rtas_token("ibm,get-system-parameter");
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -EINVAL;
+
+	local_buffer = kmalloc(sizeof(*local_buffer), GFP_KERNEL);
+	if (!local_buffer)
+		return -ENOMEM;
+
+	do {
+		spin_lock(&rtas_data_buf_lock);
+		memset(rtas_data_buf, 0, sizeof(*local_buffer));
+		rc = rtas_call(token, 3, 1, NULL, SPLPAR_LPAR_NAME_TOKEN,
+			       __pa(rtas_data_buf), sizeof(*local_buffer));
+		if (!rc)
+			memcpy(local_buffer->raw_buffer, rtas_data_buf,
+			       sizeof(local_buffer->raw_buffer));
+		spin_unlock(&rtas_data_buf_lock);
+	} while (rtas_busy_delay(rc));
+
+	if (!rc) {
+		/* Force end of string */
+		len = min((int) be16_to_cpu(local_buffer->len),
+			  (int) sizeof(local_buffer->name)-1);
+		local_buffer->name[len] = '\0';
+
+		seq_printf(m, "partition_name=%s\n", local_buffer->name);
+	} else
+		rc = -ENODATA;
+
+	kfree(local_buffer);
+	return rc;
+}
+
+/**
+ * Read the LPAR name from the Device Tree.
+ *
+ * The value read in the DT is not updated if the end-user is touching the LPAR
+ * name on the hypervisor side.
+ */
+static int read_DT_lpar_name(struct seq_file *m)
+{
+	struct device_node *rootdn;
+	const char *name;
+
+	rootdn = of_find_node_by_path("/");
+	if (!rootdn)
+		return -ENOENT;
+
+	name = of_get_property(rootdn, "ibm,partition-name", NULL);
+	if (!name)
+		return -ENOENT;
+
+	seq_printf(m, "partition_name=%s\n", name);
+	return 0;
+}
+
+static void read_lpar_name(struct seq_file *m)
+{
+	if (read_RTAS_lpar_name(m) && read_DT_lpar_name(m))
+		pr_err_once("Error can't get the LPAR name");
+}
+
 #define SPLPAR_CHARACTERISTICS_TOKEN 20
 #define SPLPAR_MAXLENGTH 1026*(sizeof(char))

@@ -496,6 +588,7 @@ static int pseries_lparcfg_data(struct seq_file *m, void *v)
 
 	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 		/* this call handles the ibm,get-system-parameter contents */
+		read_lpar_name(m);
 		parse_system_parameter_string(m);
 		parse_ppp_data(m);
 		parse_mpp_data(m);

Re: [PATCH v5] powerpc/pseries: read the lpar name from the firmware

From: kernel test robot <hidden>
Date: 2022-01-10 13:34:04

Hi Laurent,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on linux/master linus/master v5.16 next-20220110]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Laurent-Dufour/powerpc-pseries-read-the-lpar-name-from-the-firmware/20220107-001503
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc64-randconfig-r026-20220106 (https://download.01.org/0day-ci/archive/20220110/202201102154.a95OQEPr-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/5cf0dea6e919e93ff3088f87acd40e84608a6861
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Laurent-Dufour/powerpc-pseries-read-the-lpar-name-from-the-firmware/20220107-001503
        git checkout 5cf0dea6e919e93ff3088f87acd40e84608a6861
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/platforms/pseries/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

   arch/powerpc/platforms/pseries/lparcfg.c:257: warning: Function parameter or member 'm' not described in 'parse_mpp_data'
   arch/powerpc/platforms/pseries/lparcfg.c:295: warning: Function parameter or member 'm' not described in 'parse_mpp_x_data'
   arch/powerpc/platforms/pseries/lparcfg.c:334: warning: Function parameter or member 'm' not described in 'read_RTAS_lpar_name'

quoted

arch/powerpc/platforms/pseries/lparcfg.c:334: warning: expecting prototype for Read the lpar name using the RTAS ibm,get-system(). Prototype was for read_RTAS_lpar_name() instead
arch/powerpc/platforms/pseries/lparcfg.c:378: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

    * Read the LPAR name from the Device Tree.
   arch/powerpc/platforms/pseries/lparcfg.c:678: warning: Function parameter or member 'entitlement' not described in 'update_mpp'
   arch/powerpc/platforms/pseries/lparcfg.c:678: warning: Function parameter or member 'weight' not described in 'update_mpp'


vim +334 arch/powerpc/platforms/pseries/lparcfg.c

   323	
   324	/**
   325	 * Read the lpar name using the RTAS ibm,get-system-parameter call.
   326	 *
   327	 * The name read through this call is updated if changes are made by the end
   328	 * user on the hypervisor side.
   329	 *
   330	 * Some hypervisor (like Qemu) may not provide this value. In that case, a non
   331	 * null value is returned.
   332	 */
   333	static int read_RTAS_lpar_name(struct seq_file *m)
 > 334	{
   335		int rc, len, token;
   336		union {
   337			char raw_buffer[GET_SYS_PARM_BUF_SIZE];
   338			struct {
   339				__be16 len;
   340				char name[GET_SYS_PARM_BUF_SIZE-2];
   341			};
   342		} *local_buffer;
   343	
   344		token = rtas_token("ibm,get-system-parameter");
   345		if (token == RTAS_UNKNOWN_SERVICE)
   346			return -EINVAL;
   347	
   348		local_buffer = kmalloc(sizeof(*local_buffer), GFP_KERNEL);
   349		if (!local_buffer)
   350			return -ENOMEM;
   351	
   352		do {
   353			spin_lock(&rtas_data_buf_lock);
   354			memset(rtas_data_buf, 0, sizeof(*local_buffer));
   355			rc = rtas_call(token, 3, 1, NULL, SPLPAR_LPAR_NAME_TOKEN,
   356				       __pa(rtas_data_buf), sizeof(*local_buffer));
   357			if (!rc)
   358				memcpy(local_buffer->raw_buffer, rtas_data_buf,
   359				       sizeof(local_buffer->raw_buffer));
   360			spin_unlock(&rtas_data_buf_lock);
   361		} while (rtas_busy_delay(rc));
   362	
   363		if (!rc) {
   364			/* Force end of string */
   365			len = min((int) be16_to_cpu(local_buffer->len),
   366				  (int) sizeof(local_buffer->name)-1);
   367			local_buffer->name[len] = '\0';
   368	
   369			seq_printf(m, "partition_name=%s\n", local_buffer->name);
   370		} else
   371			rc = -ENODATA;
   372	
   373		kfree(local_buffer);
   374		return rc;
   375	}
   376	
   377	/**
 > 378	 * Read the LPAR name from the Device Tree.
   379	 *
   380	 * The value read in the DT is not updated if the end-user is touching the LPAR
   381	 * name on the hypervisor side.
   382	 */
   383	static int read_DT_lpar_name(struct seq_file *m)
   384	{
   385		struct device_node *rootdn;
   386		const char *name;
   387	
   388		rootdn = of_find_node_by_path("/");
   389		if (!rootdn)
   390			return -ENOENT;
   391	
   392		name = of_get_property(rootdn, "ibm,partition-name", NULL);
   393		if (!name)
   394			return -ENOENT;
   395	
   396		seq_printf(m, "partition_name=%s\n", name);
   397		return 0;
   398	}
   399	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH v5] powerpc/pseries: read the lpar name from the firmware

From: Michael Ellerman <hidden>
Date: 2022-01-11 22:40:46

Tyrel Datwyler [off-list ref] writes:

On 1/6/22 8:13 AM, Laurent Dufour wrote:

quoted

The LPAR name may be changed after the LPAR has been started in the HMC.
In that case lparstat command is not reporting the updated value because it
reads it from the device tree which is read at boot time.

However this value could be read from RTAS.

Adding this value in the /proc/powerpc/lparcfg output allows to read the
updated value.

However the hypervisor, like Qemu/KVM, may not support this RTAS
parameter. In that case the value reported in lparcfg is read from the
device tree and so is not updated accordingly.

Cc: Nathan Lynch <redacted>
Signed-off-by: Laurent Dufour <redacted>

My only nit would be that in general for consistency with other function names
_RTAS_ and _DT_ should be lowercase. Seeing as they are statically scoped within
lparcfg.c maybe its ok. Otherwise,

Yeah I agree, I changed them to lower case when applying.

cheers

Re: [PATCH v5] powerpc/pseries: read the lpar name from the firmware

From: Laurent Dufour <hidden>
Date: 2022-01-12 13:10:31

On 11/01/2022, 23:40:27, Michael Ellerman wrote:

Tyrel Datwyler [off-list ref] writes:

quoted

On 1/6/22 8:13 AM, Laurent Dufour wrote:

quoted

The LPAR name may be changed after the LPAR has been started in the HMC.
In that case lparstat command is not reporting the updated value because it
reads it from the device tree which is read at boot time.

However this value could be read from RTAS.

Adding this value in the /proc/powerpc/lparcfg output allows to read the
updated value.

However the hypervisor, like Qemu/KVM, may not support this RTAS
parameter. In that case the value reported in lparcfg is read from the
device tree and so is not updated accordingly.

Cc: Nathan Lynch <redacted>
Signed-off-by: Laurent Dufour <redacted>

My only nit would be that in general for consistency with other function names
_RTAS_ and _DT_ should be lowercase. Seeing as they are statically scoped within
lparcfg.c maybe its ok. Otherwise,

Yeah I agree, I changed them to lower case when applying.

Thanks Michael and Tyrel.

Re: [PATCH v5] powerpc/pseries: read the lpar name from the firmware

From: Michael Ellerman <hidden>
Date: 2022-02-15 05:31:14

On Thu, 6 Jan 2022 17:13:39 +0100, Laurent Dufour wrote:

The LPAR name may be changed after the LPAR has been started in the HMC.
In that case lparstat command is not reporting the updated value because it
reads it from the device tree which is read at boot time.

However this value could be read from RTAS.

Adding this value in the /proc/powerpc/lparcfg output allows to read the
updated value.

[...]

Applied to powerpc/next.

[1/1] powerpc/pseries: read the lpar name from the firmware
      https://git.kernel.org/powerpc/c/eddaa9a402758d379520f6511fb61e89990698aa

cheers

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