[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [XEN PATCH v2 5/5] tools: add example application to initialize dom0less PV drivers
Hi Stefano, > On 13 Jan 2022, at 00:58, Stefano Stabellini <sstabellini@xxxxxxxxxx> wrote: > > From: Luca Miccio <lucmiccio@xxxxxxxxx> > > Add an example application that can be run in dom0 to complete the > dom0less domains initialization so that they can get access to xenstore > and use PV drivers. > > Signed-off-by: Luca Miccio <lucmiccio@xxxxxxxxx> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx> > CC: Wei Liu <wl@xxxxxxx> > CC: Anthony PERARD <anthony.perard@xxxxxxxxxx> > CC: Juergen Gross <jgross@xxxxxxxx> > --- > Changes in v2: > - do not set HVM_PARAM_STORE_EVTCHN twice > - rename restore_xenstore to create_xenstore > - increase maxmem > --- > tools/helpers/Makefile | 13 ++ > tools/helpers/init-dom0less.c | 266 ++++++++++++++++++++++++++++++++++ > 2 files changed, 279 insertions(+) > create mode 100644 tools/helpers/init-dom0less.c > > diff --git a/tools/helpers/Makefile b/tools/helpers/Makefile > index 7f6c422440..8e42997052 100644 > --- a/tools/helpers/Makefile > +++ b/tools/helpers/Makefile > @@ -10,6 +10,9 @@ ifeq ($(CONFIG_Linux),y) > ifeq ($(CONFIG_X86),y) > PROGS += init-xenstore-domain > endif > +ifeq ($(CONFIG_ARM),y) > +PROGS += init-dom0less > +endif > endif > > XEN_INIT_DOM0_OBJS = xen-init-dom0.o init-dom-json.o > @@ -26,6 +29,13 @@ $(INIT_XENSTORE_DOMAIN_OBJS): CFLAGS += > $(CFLAGS_libxenstore) > $(INIT_XENSTORE_DOMAIN_OBJS): CFLAGS += $(CFLAGS_libxenlight) > $(INIT_XENSTORE_DOMAIN_OBJS): CFLAGS += -include $(XEN_ROOT)/tools/config.h > > +INIT_DOM0LESS_OBJS = init-dom0less.o init-dom-json.o > +$(INIT_DOM0LESS_OBJS): CFLAGS += $(CFLAGS_libxentoollog) > +$(INIT_DOM0LESS_OBJS): CFLAGS += $(CFLAGS_libxenstore) > +$(INIT_DOM0LESS_OBJS): CFLAGS += $(CFLAGS_libxenlight) > +$(INIT_DOM0LESS_OBJS): CFLAGS += $(CFLAGS_libxenctrl) > +$(INIT_DOM0LESS_OBJS): CFLAGS += $(CFLAGS_libxenevtchn) > + > .PHONY: all > all: $(PROGS) > > @@ -35,6 +45,9 @@ xen-init-dom0: $(XEN_INIT_DOM0_OBJS) > init-xenstore-domain: $(INIT_XENSTORE_DOMAIN_OBJS) > $(CC) $(LDFLAGS) -o $@ $(INIT_XENSTORE_DOMAIN_OBJS) > $(LDLIBS_libxentoollog) $(LDLIBS_libxenstore) $(LDLIBS_libxenctrl) > $(LDLIBS_libxenguest) $(LDLIBS_libxenlight) $(APPEND_LDFLAGS) > > +init-dom0less: $(INIT_DOM0LESS_OBJS) > + $(CC) $(LDFLAGS) -o $@ $(INIT_DOM0LESS_OBJS) $(LDLIBS_libxenctrl) > $(LDLIBS_libxenevtchn) $(LDLIBS_libxentoollog) $(LDLIBS_libxenstore) > $(LDLIBS_libxenlight) $(LDLIBS_libxenguest) $(APPEND_LDFLAGS) > + > .PHONY: install > install: all > $(INSTALL_DIR) $(DESTDIR)$(LIBEXEC_BIN) > diff --git a/tools/helpers/init-dom0less.c b/tools/helpers/init-dom0less.c > new file mode 100644 > index 0000000000..0434ca064f > --- /dev/null > +++ b/tools/helpers/init-dom0less.c > @@ -0,0 +1,266 @@ > +#include <stdbool.h> > +#include <syslog.h> > +#include <stdio.h> > +#include <err.h> > +#include <stdlib.h> > +#include <xenstore.h> > +#include <xenctrl.h> > +#include <xenguest.h> > +#include <libxl.h> > +#include <xenevtchn.h> > + > +#include "init-dom-json.h" > + > +#define NR_MAGIC_PAGES 4 > +#define CONSOLE_PFN_OFFSET 0 > +#define XENSTORE_PFN_OFFSET 1 > +#define STR_MAX_LENGTH 64 > + > +static int alloc_magic_pages(libxl_dominfo *info, struct xc_dom_image *dom) > +{ > + int rc, i; > + const xen_pfn_t base = GUEST_MAGIC_BASE >> XC_PAGE_SHIFT; > + xen_pfn_t p2m[NR_MAGIC_PAGES]; > + > + rc = xc_domain_setmaxmem(dom->xch, dom->guest_domid, > + info->max_memkb + NR_MAGIC_PAGES * 4); > + if (rc < 0) > + return rc; > + > + for (i = 0; i < NR_MAGIC_PAGES; i++) > + p2m[i] = base + i; > + > + rc = xc_domain_populate_physmap_exact(dom->xch, dom->guest_domid, > + NR_MAGIC_PAGES, 0, 0, p2m); > + if (rc < 0) > + return rc; > + > + dom->xenstore_pfn = base + XENSTORE_PFN_OFFSET; > + > + xc_clear_domain_page(dom->xch, dom->guest_domid, dom->xenstore_pfn); > + > + xc_hvm_param_set(dom->xch, dom->guest_domid, HVM_PARAM_STORE_PFN, > + dom->xenstore_pfn); > + return 0; > +} > + > +static void do_xs_write(struct xs_handle *xsh, xs_transaction_t t, > + char *path, char *val) > +{ > + if (!xs_write(xsh, t, path, val, strlen(val))) > + fprintf(stderr, "writing %s to xenstore failed.\n", path); Error here is ignored, do we really want that ? > +} > + > +static void do_xs_write_dom(struct xs_handle *xsh, xs_transaction_t t, > + domid_t domid, char *path, char *val) > +{ > + char full_path[STR_MAX_LENGTH]; > + > + snprintf(full_path, STR_MAX_LENGTH, > + "/local/domain/%d/%s", domid, path); > + do_xs_write(xsh, t, full_path, val); > +} > + > +static void do_xs_write_libxl(struct xs_handle *xsh, xs_transaction_t t, > + domid_t domid, char *path, char *val) > +{ > + char full_path[STR_MAX_LENGTH]; > + > + snprintf(full_path, STR_MAX_LENGTH, > + "/libxl/%d/%s", domid, path); > + do_xs_write(xsh, t, full_path, val); > +} > + > +static void do_xs_write_vm(struct xs_handle *xsh, xs_transaction_t t, > + libxl_uuid uuid, char *path, char *val) > +{ > + char full_path[STR_MAX_LENGTH]; > + > + snprintf(full_path, STR_MAX_LENGTH, > + "/vm/" LIBXL_UUID_FMT "/%s", LIBXL_UUID_BYTES(uuid), path); > + do_xs_write(xsh, t, full_path, val); > +} > + > +static int restore_xenstore(struct xs_handle *xsh, > + libxl_dominfo *info, libxl_uuid uuid, > + evtchn_port_t xenstore_port) > +{ > + domid_t domid; > + int i; > + char uuid_str[STR_MAX_LENGTH]; > + char dom_name_str[STR_MAX_LENGTH]; > + char vm_val_str[STR_MAX_LENGTH]; > + char id_str[STR_MAX_LENGTH]; > + char max_memkb_str[STR_MAX_LENGTH]; > + char cpu_str[STR_MAX_LENGTH]; > + char xenstore_port_str[STR_MAX_LENGTH]; > + char ring_ref_str[STR_MAX_LENGTH]; > + xs_transaction_t t; > + > + domid = info->domid; > + snprintf(id_str, STR_MAX_LENGTH, "%d", domid); > + snprintf(dom_name_str, STR_MAX_LENGTH, "dom0less-%d", domid); > + snprintf(uuid_str, STR_MAX_LENGTH, LIBXL_UUID_FMT, > LIBXL_UUID_BYTES(uuid)); > + snprintf(vm_val_str, STR_MAX_LENGTH, > + "vm/" LIBXL_UUID_FMT, LIBXL_UUID_BYTES(uuid)); > + snprintf(max_memkb_str, STR_MAX_LENGTH, "%lu", info->max_memkb); > + snprintf(ring_ref_str, STR_MAX_LENGTH, "%lld", > + (GUEST_MAGIC_BASE >> XC_PAGE_SHIFT) + XENSTORE_PFN_OFFSET); > + snprintf(xenstore_port_str, STR_MAX_LENGTH, "%d", xenstore_port); > + > +retry_transaction: > + t = xs_transaction_start(xsh); > + if (t == XBT_NULL) > + return errno; > + All the following is very static and for a dummy reviewer (like me) kind of magic. Could you add a comment on top of this explaining how this list of entries was created so that someone updating/reviewing this code can make sure it is right ? > + /* /vm */ > + do_xs_write_vm(xsh, t, uuid, "name", dom_name_str); > + do_xs_write_vm(xsh, t, uuid, "uuid", uuid_str); > + do_xs_write_vm(xsh, t, uuid, "start_time", "0"); > + > + /* /domain */ > + do_xs_write_dom(xsh, t, domid, "vm", vm_val_str); > + do_xs_write_dom(xsh, t, domid, "name", dom_name_str); > + do_xs_write_dom(xsh, t, domid, "cpu", ""); > + for (i = 0; i < info->vcpu_max_id; i++) { > + snprintf(cpu_str, STR_MAX_LENGTH, "cpu/%d/availability/", i); > + do_xs_write_dom(xsh, t, domid, cpu_str, > + (info->cpupool & (1 << i)) ? "online" : "offline"); > + } > + do_xs_write_dom(xsh, t, domid, "cpu/0", ""); > + do_xs_write_dom(xsh, t, domid, "cpu/availability", "online"); > + > + do_xs_write_dom(xsh, t, domid, "memory", ""); > + do_xs_write_dom(xsh, t, domid, "memory/static-max", max_memkb_str); > + do_xs_write_dom(xsh, t, domid, "memory/videoram", "-1"); > + > + do_xs_write_dom(xsh, t, domid, "device", ""); > + do_xs_write_dom(xsh, t, domid, "device/suspend", ""); > + do_xs_write_dom(xsh, t, domid, "device/suspend/event-channel", ""); > + > + do_xs_write_dom(xsh, t, domid, "control", ""); > + do_xs_write_dom(xsh, t, domid, "control/shutdown", ""); > + do_xs_write_dom(xsh, t, domid, "control/feature-poweroff", "1"); > + do_xs_write_dom(xsh, t, domid, "control/feature-reboot", "1"); > + do_xs_write_dom(xsh, t, domid, "control/feature-suspend", ""); > + do_xs_write_dom(xsh, t, domid, "control/sysrq", ""); > + do_xs_write_dom(xsh, t, domid, > "control/platform-feature-multiprocessor-suspend", "1"); > + do_xs_write_dom(xsh, t, domid, "control", > "platform-feature-xs_reset_watches"); > + > + do_xs_write_dom(xsh, t, domid, "domid", id_str); > + do_xs_write_dom(xsh, t, domid, "data", ""); > + do_xs_write_dom(xsh, t, domid, "drivers", ""); > + do_xs_write_dom(xsh, t, domid, "feature", ""); > + do_xs_write_dom(xsh, t, domid, "attr", ""); > + > + do_xs_write_dom(xsh, t, domid, "store/port", xenstore_port_str); > + do_xs_write_dom(xsh, t, domid, "store/ring-ref", ring_ref_str); > + > + do_xs_write_libxl(xsh, t, domid, "type", "pvh"); > + do_xs_write_libxl(xsh, t, domid, "dm-version", "qemu_xen"); > + > + if (!xs_transaction_end(xsh, t, false)) > + if (errno == EAGAIN) > + goto retry_transaction; > + > + return 0; > +} > + > +static int init_domain(struct xs_handle *xsh, libxl_dominfo *info) > +{ > + struct xc_dom_image dom; > + libxl_uuid uuid; > + uint64_t v; > + int rc; > + > + printf("#### Init dom0less domain: %d ####\n", info->domid); > + dom.guest_domid = info->domid; > + dom.xenstore_domid = 0; > + dom.xch = xc_interface_open(0, 0, 0); > + > + rc = xc_hvm_param_get(dom.xch, info->domid, HVM_PARAM_STORE_EVTCHN, &v); > + if (rc != 0) { > + printf("Failed to get HVM_PARAM_STORE_EVTCHN\n"); > + return 1; > + } > + dom.xenstore_evtchn = v; > + > + /* Console won't be initialized but set its data for completeness */ > + dom.console_domid = 0; > + > + /* Alloc magic pages */ > + printf("Allocating magic pages\n"); > + if (alloc_magic_pages(info, &dom) != 0) { > + printf("Error on alloc magic pages\n"); > + return 1; > + } > + > + printf("Setup Grant Tables\n"); > + xc_dom_gnttab_init(&dom); > + > + printf("Setup UUID\n"); > + libxl_uuid_generate(&uuid); > + xc_domain_sethandle(dom.xch, info->domid, libxl_uuid_bytearray(&uuid)); > + > + printf("Creating JSON\n"); > + rc = gen_stub_json_config(info->domid, &uuid); > + if (rc) > + err(1, "gen_stub_json_config"); > + > + printf("Restoring Xenstore values\n"); > + restore_xenstore(xsh, info, uuid, dom.xenstore_evtchn); > + > + printf("Introducing domain\n"); > + xs_introduce_domain(xsh, info->domid, > + (GUEST_MAGIC_BASE >> XC_PAGE_SHIFT) + XENSTORE_PFN_OFFSET, > + dom.xenstore_evtchn); This is really verbose and you have no option to make this a bit more quiet. Do we really need all those prints ? Could end up being a lot if you have 5 or 6 domains. > + return 0; > +} > + > +/* Check if domain has been configured in XS */ > +static bool domain_exists(struct xs_handle *xsh, int domid) > +{ > + return xs_is_domain_introduced(xsh, domid); > +} > + > +int main(int argc, char **argv) > +{ > + libxl_dominfo *info; > + libxl_ctx *ctx; > + int nb_vm, i; > + struct xs_handle *xsh; > + > + xsh = xs_daemon_open(); > + if (xsh == NULL) { > + fprintf(stderr, "Could not contact XenStore"); > + exit(1); > + } > + > + if (libxl_ctx_alloc(&ctx, LIBXL_VERSION, 0, NULL)) { > + fprintf(stderr, "cannot init xl context\n"); You might want to close xsh to be clean here > + exit(1); > + } > + > + info = libxl_list_domain(ctx, &nb_vm); > + if (!info) { > + fprintf(stderr, "libxl_list_vm failed.\n"); You might want to close xsh to be clean here > + exit(EXIT_FAILURE); Why using EXIT_FAILURE here but 1 on the exit before ? > + } > + > + for (i = 0; i < nb_vm; i++) { > + domid_t domid = info[i].domid; > + > + /* Don't need to check for Dom0 */ > + if (!domid) > + continue; > + > + printf("Checking domid: %u\n", domid); > + if (!domain_exists(xsh, domid)) > + init_domain(xsh, &info[i]); > + else > + printf("Domain %d has already been initialized\n", domid); > + } > + libxl_dominfo_list_free(info, nb_vm); > + xs_close(xsh); > + return 0; > +} > -- > 2.25.1 >
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