[Xen-devel] [PATCH v2 3/6] libxl:xl: add parsing code to parse "libxl_static_sshm" from xl config files

[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>

Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxx
---
v2:
  * fix all the 'Yoda conditions'
  * use the predefined XC_PAGE_MASK instead of defining a new one
---
 tools/libxl/Makefile      |   2 +-
 tools/libxl/libxlu_sshm.c | 210 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxlutil.h   |   6 ++
 tools/xl/xl_parse.c       |  24 +++++-
 4 files changed, 240 insertions(+), 2 deletions(-)
 create mode 100644 tools/libxl/libxlu_sshm.c

diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index 082af8f716..3b63fb2cad 100644
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -175,7 +175,7 @@ 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 += $(CFLAGS_libxentoollog)
diff --git a/tools/libxl/libxlu_sshm.c b/tools/libxl/libxlu_sshm.c
new file mode 100644
index 0000000000..5276ff9395
--- /dev/null
+++ b/tools/libxl/libxlu_sshm.c
@@ -0,0 +1,210 @@
+#include "libxl_osdeps.h" /* must come before any other headers */
+#include "libxlu_internal.h"
+#include "xenctrl.h"
+
+#include <ctype.h>
+
+#define PARAM_RE(EXPR) "^\\s*" EXPR "\\s*(,|$)"
+#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, "end") ||
+               !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/end/offset", val);
+        if (new_addr & ~XC_PAGE_MASK)
+            RET_INVAL("begin/end/offset is not a multiple of 4K", val);
+
+        /* begin or end */
+        if (key[0] == 'b') {
+            SET_VAL(sshm->begin, "beginning address", RANGE, new_addr, val);
+        } else if(key[0] == 'e'){
+            SET_VAL(sshm->end, "ending address", 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->end == LIBXL_SSHM_RANGE_UNKNOWN) {
+        RET_INVAL("end address not specified", spec);
+    }
+    if (sshm->begin > sshm->end) {
+        RET_INVAL("begin address larger that end address", spec);
+    }
+
+    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 e81b644c01..ee39cb5bdc 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 5c2bf17222..82d955b8b9 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -813,7 +813,7 @@ 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;
+                   *usbctrls, *usbdevs, *p9devs, *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;
@@ -1392,6 +1392,28 @@ 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;
-- 
2.14.0


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