[Xen-devel] [PATCH v5 5/6] libxl:xl: add parsing code to parse "libxl_static_sshm" from xl config files

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

From: Zhongze Liu <blackskygg@xxxxxxxxx>

Author: Zhongze Liu <blackskygg@xxxxxxxxx>

Add the parsing utils for the newly introduced libxl_static_sshm struct
to the libxl/libxlu_* family. And add realated parsing code in xl to
parse the struct from xl config files. This is for the proposal "Allow
setting up shared memory areas between VMs from xl config file" (see [1]).

[1] https://lists.xen.org/archives/html/xen-devel/2017-08/msg03242.html

Signed-off-by: Zhongze Liu <blackskygg@xxxxxxxxx>
Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>

Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxx
---
Changes in v5:
- remove alignment checks, they were moved to libxl
---
 tools/libxl/Makefile      |   2 +-
 tools/libxl/libxlu_sshm.c | 207 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxlutil.h   |   6 ++
 tools/xl/xl_parse.c       |  25 +++++-
 4 files changed, 238 insertions(+), 2 deletions(-)
 create mode 100644 tools/libxl/libxlu_sshm.c

diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index 3b762c5..2920f7e 100644
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -176,7 +176,7 @@ AUTOINCS= libxlu_cfg_y.h libxlu_cfg_l.h _libxl_list.h 
_paths.h \
 AUTOSRCS= libxlu_cfg_y.c libxlu_cfg_l.c
 AUTOSRCS += _libxl_save_msgs_callout.c _libxl_save_msgs_helper.c
 LIBXLU_OBJS = libxlu_cfg_y.o libxlu_cfg_l.o libxlu_cfg.o \
-       libxlu_disk_l.o libxlu_disk.o libxlu_vif.o libxlu_pci.o
+       libxlu_disk_l.o libxlu_disk.o libxlu_vif.o libxlu_pci.o libxlu_sshm.o
 $(LIBXLU_OBJS): CFLAGS += $(CFLAGS_libxenctrl) # For xentoollog.h
 
 $(TEST_PROG_OBJS) _libxl.api-for-check: CFLAGS += $(CFLAGS_libxentoollog) 
$(CFLAGS_libxentoolcore)
diff --git a/tools/libxl/libxlu_sshm.c b/tools/libxl/libxlu_sshm.c
new file mode 100644
index 0000000..cc709a7
--- /dev/null
+++ b/tools/libxl/libxlu_sshm.c
@@ -0,0 +1,207 @@
+#include "libxl_osdeps.h" /* must come before any other headers */
+#include "libxlu_internal.h"
+#include "xenctrl.h"
+
+#include <ctype.h>
+
+#define PARAM_RE(EXPR) "^\\s*" EXPR "\\s*(,|$)"
+#define WORD_RE         "([_a-zA-Z0-9]+)"
+#define EQU_RE         PARAM_RE(WORD_RE "\\s*=\\s*" WORD_RE)
+
+#define RET_INVAL(msg, curr_str)  do {              \
+        xlu__sshm_err(cfg, msg, curr_str);          \
+        rc = EINVAL;                                \
+        goto out;                                   \
+    } while(0)
+
+/* set a member in libxl_static_shm and report an error if it's respecified,
+ * @curr_str indicates the head of the remaining string. */
+#define SET_VAL(var, name, type, value, curr_str)  do {                 \
+        if ((var) != LIBXL_SSHM_##type##_UNKNOWN && (var) != value) {   \
+            RET_INVAL("\"" name "\" respecified", curr_str);            \
+        }                                                               \
+        (var) = value;                                                  \
+    } while(0)
+
+
+static void xlu__sshm_err(XLU_Config *cfg, const char *msg,
+                          const char *curr_str) {
+    fprintf(cfg->report,
+            "%s: config parsing error in shared_memory: %s at '%s'\n",
+            cfg->config_source, msg, curr_str);
+}
+
+static int parse_prot(XLU_Config *cfg, char *str, libxl_sshm_prot *prot)
+{
+    int rc;
+    libxl_sshm_prot new_prot;
+
+    if (!strcmp(str, "rw")) {
+        new_prot = LIBXL_SSHM_PROT_RW;
+    } else {
+        RET_INVAL("invalid permission flags", str);
+    }
+
+    SET_VAL(*prot, "permission flags", PROT, new_prot, str);
+
+    rc = 0;
+
+ out:
+    return rc;
+}
+
+static int parse_cachepolicy(XLU_Config *cfg, char *str,
+                             libxl_sshm_cachepolicy *policy)
+{
+    int rc;
+    libxl_sshm_cachepolicy new_policy;
+
+    if (!strcmp(str, "ARM_normal")) {
+        new_policy = LIBXL_SSHM_CACHEPOLICY_ARM_NORMAL;
+    } else if (!strcmp(str, "x86_normal")) {
+        new_policy = LIBXL_SSHM_CACHEPOLICY_X86_NORMAL;
+    } else {
+        RET_INVAL("invalid cache policy", str);
+    }
+
+    SET_VAL(*policy, "cache policy", CACHEPOLICY, new_policy, str);
+    rc = 0;
+
+ out:
+    return rc;
+}
+
+/* handle key = value pairs */
+static int handle_equ(XLU_Config *cfg, char *key, char *val,
+                      libxl_static_shm *sshm)
+{
+    int rc;
+
+    if (!strcmp(key, "id")) {
+        if (strlen(val) > LIBXL_SSHM_ID_MAXLEN) { RET_INVAL("id too long", 
val); }
+        if (sshm->id && !strcmp(sshm->id, val)) {
+            RET_INVAL("id respecified", val);
+        }
+
+        sshm->id = strdup(val);
+        if (!sshm->id) {
+            fprintf(stderr, "sshm parser out of memory\n");
+            rc = ENOMEM;
+            goto out;
+        }
+    } else if (!strcmp(key, "role")) {
+        libxl_sshm_role new_role;
+
+        if (!strcmp("master", val)) {
+            new_role = LIBXL_SSHM_ROLE_MASTER;
+        } else if (!strcmp("slave", val)) {
+            new_role = LIBXL_SSHM_ROLE_SLAVE;
+        } else {
+            RET_INVAL("invalid role", val);
+        }
+
+        SET_VAL(sshm->role, "role", ROLE, new_role, val);
+    } else if (!strcmp(key, "begin") ||
+               !strcmp(key, "size") ||
+               !strcmp(key, "offset")) {
+        char *endptr;
+        int base = 10;
+        uint64_t new_addr;
+
+        /* Could be in hex form. Note that we don't need to check the length 
here,
+         * for val[] is NULL-terminated */
+        if (val[0] == '0' && val[1] == 'x') { base = 16; }
+        new_addr = strtoull(val, &endptr, base);
+        if (errno == ERANGE || *endptr)
+            RET_INVAL("invalid begin/size/offset", val);
+
+        if (key[0] == 'b') {
+            SET_VAL(sshm->begin, "beginning address", RANGE, new_addr, val);
+        } else if(key[0] == 's'){
+            SET_VAL(sshm->size, "size", RANGE, new_addr, val);
+        } else {
+            SET_VAL(sshm->offset, "offset", RANGE, new_addr, val);
+        }
+    } else if (!strcmp(key, "prot")) {
+        rc = parse_prot(cfg, val, &sshm->prot);
+        if (rc) { goto out; }
+    } else if (!strcmp(key, "cache_policy")) {
+        rc = parse_cachepolicy(cfg, val, &sshm->cache_policy);
+        if (rc) { goto out; }
+    } else {
+        RET_INVAL("invalid option", key);
+    }
+
+    rc = 0;
+
+ out:
+    return rc;
+}
+
+int xlu_sshm_parse(XLU_Config *cfg, const char *spec,
+                   libxl_static_shm *sshm)
+{
+    int rc;
+    regex_t equ_rec;
+    char *buf2 = NULL, *ptr = NULL;
+    regmatch_t pmatch[3];
+
+    rc = regcomp(&equ_rec, EQU_RE, REG_EXTENDED);
+    if (rc) {
+        fprintf(stderr, "sshm parser failed to initialize\n");
+        goto out;
+    }
+
+    buf2 = ptr = strdup(spec);
+    if (!buf2) {
+        fprintf(stderr, "sshm parser out of memory\n");
+        rc = ENOMEM;
+        goto out;
+    }
+
+    /* main parsing loop */
+    while (true) {
+        if (!*ptr) { break; }
+        if (regexec(&equ_rec, ptr, 3, pmatch, 0))
+            RET_INVAL("unrecognized token", ptr);
+
+        ptr[pmatch[1].rm_eo] = '\0';
+        ptr[pmatch[2].rm_eo] = '\0';
+        rc = handle_equ(cfg, ptr + pmatch[1].rm_so,
+                        ptr + pmatch[2].rm_so, sshm);
+        if (rc) { goto out; }
+
+        ptr += pmatch[0].rm_eo;
+    }
+
+    if (*ptr) { RET_INVAL("invalid syntax", ptr); }
+
+    /* do some early checks */
+    if (!sshm->id) {
+        RET_INVAL("id not specified", spec);
+    }
+    if (sshm->begin == LIBXL_SSHM_RANGE_UNKNOWN) {
+        RET_INVAL("begin address not specified", spec);
+    }
+    if (sshm->size == LIBXL_SSHM_RANGE_UNKNOWN) {
+        RET_INVAL("size not specified", spec);
+    }
+    if (sshm->prot == LIBXL_SSHM_PROT_UNKNOWN) {
+        sshm->prot = LIBXL_SSHM_PROT_RW;
+    }
+
+    rc = 0;
+
+ out:
+    if (buf2) { free(buf2); }
+    regfree(&equ_rec);
+    return rc;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/tools/libxl/libxlutil.h b/tools/libxl/libxlutil.h
index e81b644..ee39cb5 100644
--- a/tools/libxl/libxlutil.h
+++ b/tools/libxl/libxlutil.h
@@ -118,6 +118,12 @@ int xlu_rdm_parse(XLU_Config *cfg, libxl_rdm_reserve *rdm, 
const char *str);
 int xlu_vif_parse_rate(XLU_Config *cfg, const char *rate,
                        libxl_device_nic *nic);
 
+/*
+ * static shared memory specification parsing
+ */
+int xlu_sshm_parse(XLU_Config *cfg, const char *spec,
+                   libxl_static_shm *sshm);
+
 #endif /* LIBXLUTIL_H */
 
 /*
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index e6c5448..3a5c874 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -860,7 +860,8 @@ void parse_config_data(const char *config_source,
     long l, vcpus = 0;
     XLU_Config *config;
     XLU_ConfigList *cpus, *vbds, *nics, *pcis, *cvfbs, *cpuids, *vtpms,
-                   *usbctrls, *usbdevs, *p9devs, *vdispls, *pvcallsifs_devs;
+                   *usbctrls, *usbdevs, *p9devs, *vdispls, *pvcallsifs_devs,
+                   *sshms;
     XLU_ConfigList *channels, *ioports, *irqs, *iomem, *viridian, *dtdevs,
                    *mca_caps;
     int num_ioports, num_irqs, num_iomem, num_cpus, num_viridian, num_mca_caps;
@@ -1566,6 +1567,28 @@ void parse_config_data(const char *config_source,
         }
     }
 
+    if (!xlu_cfg_get_list (config, "static_shm", &sshms, 0, 0)) {
+        d_config->num_sshms = 0;
+        d_config->sshms = NULL;
+        while ((buf = xlu_cfg_get_listitem (sshms, d_config->num_sshms)) != 
NULL) {
+            libxl_static_shm *sshm;
+            char *buf2 = strdup(buf);
+            int ret;
+
+            sshm = ARRAY_EXTEND_INIT_NODEVID(d_config->sshms,
+                                             d_config->num_sshms,
+                                             libxl_static_shm_init);
+            ret = xlu_sshm_parse(config, buf2, sshm);
+            if (ret) {
+                fprintf(stderr,
+                        "xl: Invalid argument for static_shm: %s", buf2);
+                exit(EXIT_FAILURE);
+            }
+
+            free(buf2);
+        }
+    }
+
     if (!xlu_cfg_get_list(config, "p9", &p9devs, 0, 0)) {
         libxl_device_p9 *p9;
         char *security_model = NULL;
-- 
1.9.1


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