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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [RFC PATCH 4/4] libxl: support creation and destruction of static shared memory areas
creation: * Check for further errors in the static_shm configs: overlapping areas, invalid ranges, duplicated master domain, no master domain etc. * Add code for writing infomations of static shared memory areas into the appropriate xenstore paths. * use xc_domain_add_to_physmap_batch to do the page sharing. destruction: * Check for errors that try to remove master while there'are still living slaves. * Cleanup related xenstore paths. This is for the proposal "Allow setting up shared memory areas between VMs from xl config file" (see [1]). [1] https://lists.xenproject.org/archives/html/xen-devel/2017-07/msg03047.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 --- tools/libxl/Makefile | 2 +- tools/libxl/libxl_create.c | 7 + tools/libxl/libxl_dom.c | 7 + tools/libxl/libxl_domain.c | 6 + tools/libxl/libxl_internal.h | 14 ++ tools/libxl/libxl_sshm.c | 370 +++++++++++++++++++++++++++++++++++++++++++ tools/libxl/libxl_xshelp.c | 8 + 7 files changed, 413 insertions(+), 1 deletion(-) create mode 100644 tools/libxl/libxl_sshm.c diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile index 3b63fb2cad..fd624b28f3 100644 --- a/tools/libxl/Makefile +++ b/tools/libxl/Makefile @@ -138,7 +138,7 @@ LIBXL_OBJS = flexarray.o libxl.o libxl_create.o libxl_dm.o libxl_pci.o \ libxl_dom_suspend.o libxl_dom_save.o libxl_usb.o \ libxl_vtpm.o libxl_nic.o libxl_disk.o libxl_console.o \ libxl_cpupool.o libxl_mem.o libxl_sched.o libxl_tmem.o \ - libxl_9pfs.o libxl_domain.o \ + libxl_9pfs.o libxl_domain.o libxl_sshm.o \ $(LIBXL_OBJS-y) LIBXL_OBJS += libxl_genid.o LIBXL_OBJS += _libxl_types.o libxl_flask.o _libxl_types_internal.o diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c index 1158303e1a..06dba2178d 100644 --- a/tools/libxl/libxl_create.c +++ b/tools/libxl/libxl_create.c @@ -918,6 +918,13 @@ static void initiate_domain_create(libxl__egc *egc, goto error_out; } + if (d_config->c_info.type != LIBXL_DOMAIN_TYPE_HVM && + d_config->num_sshms != 0) { + LOGD(ERROR, domid, "static_shm is only applicable to HVM domains"); + ret = ERROR_INVAL; + goto error_out; + } + ret = libxl__domain_make(gc, d_config, &domid, &state->config); if (ret) { LOGD(ERROR, domid, "cannot make domain: %d", ret); diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c index f54fd49a73..1958667344 100644 --- a/tools/libxl/libxl_dom.c +++ b/tools/libxl/libxl_dom.c @@ -1194,6 +1194,13 @@ int libxl__build_hvm(libxl__gc *gc, uint32_t domid, goto out; } + /* the p2m has been setup, we could map the static shared memory now. */ + rc = libxl__sshm_add(gc, domid, d_config->sshms, d_config->num_sshms); + if (rc != 0) { + LOG(ERROR, "failed to map static shared memory"); + goto out; + } + rc = hvm_build_set_params(ctx->xch, domid, info, state->store_port, &state->store_mfn, state->console_port, &state->console_mfn, state->store_domid, diff --git a/tools/libxl/libxl_domain.c b/tools/libxl/libxl_domain.c index 08eccd082b..0702a575f2 100644 --- a/tools/libxl/libxl_domain.c +++ b/tools/libxl/libxl_domain.c @@ -1028,6 +1028,12 @@ void libxl__destroy_domid(libxl__egc *egc, libxl__destroy_domid_state *dis) goto out; } + rc = libxl__sshm_del(gc, domid); + if (rc) { + LOGD(ERROR, domid, "Deleting static shm failed."); + goto out; + } + if (libxl__device_pci_destroy_all(gc, domid) < 0) LOGD(ERROR, domid, "Pci shutdown failed"); rc = xc_domain_pause(ctx->xch, domid); diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h index 724750967c..9c9f69c50f 100644 --- a/tools/libxl/libxl_internal.h +++ b/tools/libxl/libxl_internal.h @@ -721,6 +721,7 @@ _hidden char **libxl__xs_directory(libxl__gc *gc, xs_transaction_t t, const char *path, unsigned int *nb); /* On error: returns NULL, sets errno (no logging) */ _hidden char *libxl__xs_libxl_path(libxl__gc *gc, uint32_t domid); +_hidden char *libxl__xs_get_sshmpath(libxl__gc *gc, const char *id); _hidden int libxl__backendpath_parse_domid(libxl__gc *gc, const char *be_path, libxl_domid *domid_out); @@ -4353,6 +4354,19 @@ static inline bool libxl__acpi_defbool_val(const libxl_domain_build_info *b_info #endif /* + * Set up static shared ram pages for HVM domains to communicate + * + * This function should only be called after the memory map is constructed + * and before any further memory access. */ +int libxl__sshm_add(libxl__gc *gc, uint32_t domid, + libxl_static_shm *sshm, int len); + +int libxl__sshm_del(libxl__gc *gc, uint32_t domid); + +int libxl__sshm_check_slaves_overlap(libxl__gc *gc, uint32_t domid, + libxl_static_shm *sshms, int len); + +/* * Local variables: * mode: C * c-basic-offset: 4 diff --git a/tools/libxl/libxl_sshm.c b/tools/libxl/libxl_sshm.c new file mode 100644 index 0000000000..c7e9b8c1ee --- /dev/null +++ b/tools/libxl/libxl_sshm.c @@ -0,0 +1,370 @@ +#include "libxl_osdeps.h" +#include "libxl_internal.h" +#include <stdio.h> + +#define TRY_TRANSACTION_OR_FAIL(aborting) do { \ + if (!xs_transaction_end(CTX->xsh, xt, aborting) && !aborting) { \ + if (EAGAIN == errno) { \ + goto retry_transaction; \ + } else { \ + rc = ERROR_FAIL; \ + } \ + } \ + }while(0); + +#define SSHM_ERROR(domid, sshmid, f, ...) \ + LOGD(ERROR, domid, "static_shm id = %s:" f, sshmid, ##__VA_ARGS__) + + +/* The caller have to guarentee that {s,m}begin < {s,m}end */ +static int libxl__sshm_do_map(libxl__gc *gc, uint32_t mid, uint32_t sid, + libxl_static_shm *sshm, + uint64_t mbegin, uint64_t mend) +{ + int rc; + int i; + unsigned int num_mpages, num_spages, offset; + int *errs; + xen_ulong_t *idxs; + xen_pfn_t *gpfns; + + num_mpages = (mend - mbegin) >> 12; + num_spages = (sshm->end - sshm->begin) >> 12; + offset = sshm->offset >> 12; + + /* Check range. Test offset < mpages first to avoid overflow */ + if ((offset >= num_mpages) || (num_mpages - offset < num_spages)) { + SSHM_ERROR(sid, sshm->id, "exceeds master's address space."); + rc = ERROR_INVAL; + goto out; + } + + /* fill out the pfn's and do the mapping */ + errs = libxl__calloc(gc, num_spages, sizeof(int)); + idxs = libxl__calloc(gc, num_spages, sizeof(xen_ulong_t)); + gpfns = libxl__calloc(gc, num_spages, sizeof(xen_pfn_t)); + for (i = 0; i < num_spages; i++) { + idxs[i] = (mbegin >> 12) + offset + i; + gpfns[i]= (sshm->begin >> 12) + i; + } + rc = xc_domain_add_to_physmap_batch(CTX->xch, + sid, mid, + XENMAPSPACE_gmfn_foreign, + num_spages, + idxs, gpfns, errs); + + for (i = 0; i< num_spages; i++) { + if (errs[i]) { + SSHM_ERROR(sid, sshm->id, + "can't map at address 0x%"PRIx64".", + sshm->begin + (offset << 12) ); + rc = ERROR_FAIL; + } + } + if (rc) { goto out; } + + rc = 0; + + out: + return rc; +} + +static int libxl__sshm_add_master(libxl__gc *gc, uint32_t domid, + libxl_static_shm *sshm) +{ + int rc, aborting; + char *sshm_path, *dom_path, *dom_role_path; + char *ents[11]; + struct xs_permissions noperm; + xs_transaction_t xt = XBT_NULL; + + sshm_path = libxl__xs_get_sshmpath(gc, sshm->id); + dom_path = libxl__xs_get_dompath(gc, domid); + /* the domain should be in xenstore by now */ + assert(dom_path); + dom_role_path = GCSPRINTF("%s/static_shm/%s/role", dom_path, sshm->id); + + + retry_transaction: + /* Within the transaction, goto out by default means aborting */ + aborting = 1; + rc = libxl__xs_transaction_start(gc, &xt); + if (rc) { goto out; } + + if (NULL == libxl__xs_read(gc, xt, sshm_path)) { + rc = libxl__xs_write_checked(gc, xt, dom_role_path, "master"); + if (rc) { goto out; }; + + ents[0] = "master"; + ents[1] = GCSPRINTF("%"PRIu32, domid); + ents[2] = "begin"; + ents[3] = GCSPRINTF("0x%"PRIx64, sshm->begin); + ents[4] = "end"; + ents[5] = GCSPRINTF("0x%"PRIx64, sshm->end); + ents[6] = "prot"; + ents[7] = libxl__strdup(gc, libxl_sshm_prot_to_string(sshm->prot)); + ents[8] = "cache_policy"; + ents[9] = libxl__strdup(gc, + libxl_sshm_cachepolicy_to_string(sshm->cache_policy)); + ents[10] = NULL; + + /* could only be accessed by Dom0 */ + noperm.id = 0; + noperm.perms = XS_PERM_NONE; + libxl__xs_mknod(gc, xt, sshm_path, &noperm, 1); + libxl__xs_writev(gc, xt, sshm_path, ents); + } else { + SSHM_ERROR(domid, sshm->id, "can only have one master."); + rc = ERROR_FAIL; + goto out; + } + + aborting = rc = 0; + + out: + TRY_TRANSACTION_OR_FAIL(aborting); + return rc; +} + +static int libxl__sshm_add_slave(libxl__gc *gc, uint32_t domid, + libxl_static_shm *sshm) +{ + int rc, aborting; + char *sshm_path, *slave_path, *dom_path, *dom_sshm_path, *dom_role_path; + char *ents[9]; + const char *xs_value; + libxl_static_shm master_sshm; + uint32_t master_domid; + xs_transaction_t xt = XBT_NULL; + + sshm_path = libxl__xs_get_sshmpath(gc, sshm->id); + slave_path = GCSPRINTF("%s/slaves/%"PRIu32, sshm_path, domid); + dom_path = libxl__xs_get_dompath(gc, domid); + /* the domain should be in xenstore by now */ + assert(dom_path); + dom_sshm_path = GCSPRINTF("%s/static_shm/%s", dom_path, sshm->id); + dom_role_path = GCSPRINTF("%s/role", dom_sshm_path); + + retry_transaction: + /* Within the transaction, goto out by default means aborting */ + aborting = 1; + rc = libxl__xs_transaction_start(gc, &xt); + if (rc) { goto out; } + + if (NULL == libxl__xs_read(gc, xt, sshm_path)) { + SSHM_ERROR(domid, sshm->id, "no master found."); + rc = ERROR_FAIL; + goto out; + } else { + /* check the master info to see if we could do the mapping */ + if (NULL != libxl__xs_read(gc, xt, dom_sshm_path)) { + SSHM_ERROR(domid, sshm->id, + "domain tried to share the same region twice."); + rc = ERROR_FAIL; + goto out; + } + + rc = libxl__xs_read_checked(gc, xt, + GCSPRINTF("%s/prot", sshm_path), + &xs_value); + if (rc) { goto out; } + libxl_sshm_prot_from_string(xs_value, &master_sshm.prot); + + rc = libxl__xs_read_checked(gc, xt, + GCSPRINTF("%s/begin", sshm_path), + &xs_value); + if (rc) { goto out; } + master_sshm.begin = strtoull(xs_value, NULL, 16); + + rc = libxl__xs_read_checked(gc, xt, + GCSPRINTF("%s/end", sshm_path), + &xs_value); + if (rc) { goto out; } + master_sshm.end = strtoull(xs_value, NULL, 16); + + rc = libxl__xs_read_checked(gc, xt, + GCSPRINTF("%s/master", sshm_path), + &xs_value); + if (rc) { goto out; } + master_domid = strtoull(xs_value, NULL, 16); + + /* check if the slave is asking too much permission */ + if (LIBXL_SSHM_PROT_UNKNOWN == sshm->prot) { + sshm->prot = master_sshm.prot; + } + if (master_sshm.prot < sshm->prot) { + SSHM_ERROR(domid, sshm->id, "slave is asking too much permission."); + rc = ERROR_INVAL; + goto out; + } + + /* all checks passed, do the job */ + rc = libxl__sshm_do_map(gc, master_domid, domid, sshm, + master_sshm.begin, master_sshm.end); + if (rc) { + rc = ERROR_INVAL; + goto out; + } + + rc = libxl__xs_write_checked(gc, xt, dom_role_path, "slave"); + if (rc) { goto out; } + + /* fill in slave info */ + ents[0] = "begin"; + ents[1] = GCSPRINTF("0x%"PRIx64, sshm->begin); + ents[2] = "end"; + ents[3] = GCSPRINTF("0x%"PRIx64, sshm->end); + ents[4] = "offset"; + ents[5] = GCSPRINTF("0x%"PRIx64, sshm->offset); + ents[6] = "prot"; + ents[7] = libxl__strdup(gc, libxl_sshm_prot_to_string(sshm->prot)); + ents[8] = NULL; + libxl__xs_writev(gc, xt, slave_path, ents); + } + + aborting = rc = 0; + + out: + TRY_TRANSACTION_OR_FAIL(aborting); + return rc; +} + +/* Compare function for sorting sshm ranges by sshm->begin */ +static int sshm_range_cmp(const void *a, const void *b) +{ + libxl_static_shm *const *sshma = a, *const *sshmb = b; + return (*sshma)->begin > (*sshmb)->begin ? 1 : -1; +} + +/* check if the sshm slave configs in @sshm overlap */ +static int libxl__sshm_check_overlap(libxl__gc *gc, uint32_t domid, + libxl_static_shm *sshms, int len) +{ + + const libxl_static_shm **slave_sshms = NULL; + int num_slaves; + int i; + + slave_sshms = libxl__calloc(gc, len, sizeof(slave_sshms[0])); + num_slaves = 0; + for (i = 0; i < len; ++i) { + if (LIBXL_SSHM_ROLE_SLAVE == sshms[i].role) + slave_sshms[num_slaves++] = sshms + i; + } + qsort(slave_sshms, num_slaves, sizeof(slave_sshms[0]), sshm_range_cmp); + + for (i = 0; i < num_slaves - 1; ++i) { + if (slave_sshms[i+1]->begin < slave_sshms[i]->end) { + SSHM_ERROR(domid, slave_sshms[i+1]->id, "slave ranges overlap."); + return ERROR_INVAL; + } + } + + return 0; +} + +static int libxl__sshm_del_single(libxl__gc *gc, xs_transaction_t xt, + uint32_t domid, const char *id, bool master) +{ + char *sshm_path, *slaves_path; + + sshm_path = libxl__xs_get_sshmpath(gc, id); + slaves_path = GCSPRINTF("%s/slaves", sshm_path); + + if (master) { + /* we know that domid can't be both a master and a slave for one id, + * so the number of slaves won't change during iteration. Simply check + * sshm_path/slavea to tell if there are still living slaves. */ + if (NULL != libxl__xs_read(gc, xt, slaves_path)) { + SSHM_ERROR(domid, id, + "can't remove master when there are living slaves."); + return ERROR_FAIL; + } + libxl__xs_path_cleanup(gc, xt, sshm_path); + } else { + libxl__xs_path_cleanup(gc, xt, + GCSPRINTF("%s/%"PRIu32, slaves_path, domid)); + } + + return 0; +} + +/* Delete an static_shm entry in the xensotre. Will also return success if + * the path doesn't exist. */ +int libxl__sshm_del(libxl__gc *gc, uint32_t domid) +{ + int rc, aborting; + xs_transaction_t xt = XBT_NULL; + char *dom_path, *dom_sshm_path; + const char *role; + char **sshm_ents; + unsigned int sshm_num; + int i; + + if (LIBXL_DOMAIN_TYPE_HVM != libxl__domain_type(gc, domid)) + return 0; + + dom_path = libxl__xs_get_dompath(gc, domid); + dom_sshm_path = GCSPRINTF("%s/static_shm", dom_path); + + retry_transaction: + /* Within the transaction, goto out by default means aborting */ + aborting = 1; + rc = libxl__xs_transaction_start(gc, &xt); + if (rc) { goto out; } + + if (NULL == libxl__xs_read(gc, xt, dom_sshm_path)) { + /* no sshms, just do nothing */ + rc = aborting = 0; + goto out; + } + + sshm_ents = libxl__xs_directory(gc, xt, dom_sshm_path, &sshm_num); + + for (i = 0; i < sshm_num; ++i) { + rc = libxl__xs_read_checked(gc, xt, + GCSPRINTF("%s/%s/role", dom_sshm_path, sshm_ents[i]), &role); + if (rc) { goto out; } + + rc = libxl__sshm_del_single(gc, xt, domid, + sshm_ents[i], role[0] == 'm' ? 1 : 0); + if (rc) { goto out; } + } + + libxl__xs_path_cleanup(gc, xt, dom_sshm_path); + + aborting = rc = 0; + + out: + TRY_TRANSACTION_OR_FAIL(aborting); + return rc; +} + +int libxl__sshm_add(libxl__gc *gc, uint32_t domid, + libxl_static_shm *sshms, int len) +{ + int rc, i; + + if (LIBXL_DOMAIN_TYPE_HVM != libxl__domain_type(gc, domid)) + return 0; + rc = libxl__sshm_check_overlap(gc, domid, sshms, len); + if (rc) { return rc; }; + + for (i = 0; i < len; ++i) { + if (LIBXL_SSHM_ROLE_SLAVE == sshms[i].role) { + rc = libxl__sshm_add_slave(gc, domid, sshms+i); + } else { + rc = libxl__sshm_add_master(gc, domid, sshms+i); + } + if (rc) { return rc; }; + } + + return 0; +} +/* + * Local variables: + * mode: C + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */ diff --git a/tools/libxl/libxl_xshelp.c b/tools/libxl/libxl_xshelp.c index c4a18df353..d91fbf5fda 100644 --- a/tools/libxl/libxl_xshelp.c +++ b/tools/libxl/libxl_xshelp.c @@ -193,6 +193,14 @@ char *libxl__xs_libxl_path(libxl__gc *gc, uint32_t domid) return s; } +char *libxl__xs_get_sshmpath(libxl__gc *gc, const char *id) +{ + char *s = GCSPRINTF("/local/static_shm/%s", id); + if (!s) + LOGE(ERROR, "cannot allocate static shm path"); + return s; +} + int libxl__xs_read_mandatory(libxl__gc *gc, xs_transaction_t t, const char *path, const char **result_out) { -- 2.13.3 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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