On Tue, Mar 15, 2011 at 11:17:14PM -0400, Konrad Rzeszutek Wilk wrote:
> On Thu, Mar 10, 2011 at 11:03:25AM +0100, MAYAP christine wrote:
> > Hello,
> >
> > I'm still reading document about inter-VM communication via shared memory.
> > I found many reference about IVC.
>
> The IVC on I think is the XCP source code. Google for XCP source code
> and you should find it.
>
There's also V4V in Citrix XenClient.. sources available in the source iso.
It includes xen patches, linux kernel patches, and user space libraries
providing a socket-like API (for linux and windows).
-- Pasi
> > Is it already present in Xen? How can i use them?
>
> You could also look at gntalloc driver.
> Look in git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git #master
> tree.
>
>
> I think it pretty much does what you want. Here is test code that
> you can use to communicate between domains using mmap-ed memory.
>
>
> Courtesy of Daniel De Graaf.
>
> #include <errno.h>
> #include <fcntl.h>
> #include <unistd.h>
> #include <stdio.h>
> #include <string.h>
> #include <stdint.h>
> #include <sys/ioctl.h>
> #include <sys/mman.h>
>
> struct ioctl_gntdev_grant_ref {
> /* The domain ID of the grant to be mapped. */
> uint32_t domid;
> /* The grant reference of the grant to be mapped. */
> uint32_t ref;
> };
>
> /*
> * Allocates a new page and creates a new grant reference.
> */
> #define IOCTL_GNTALLOC_ALLOC_GREF \
> _IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
> struct ioctl_gntalloc_alloc_gref {
> /* IN parameters */
> /* The ID of the domain to be given access to the grants. */
> uint16_t domid;
> /* Flags for this mapping */
> uint16_t flags;
> /* Number of pages to map */
> uint32_t count;
> /* OUT parameters */
> /* The offset to be used on a subsequent call to mmap(). */
> uint64_t index;
> /* The grant references of the newly created grant, one per page */
> /* Variable size, depending on count */
> uint32_t gref_ids[1];
> };
>
> #define GNTALLOC_FLAG_WRITABLE 1
>
> /*
> * Deallocates the grant reference, allowing the associated page to be freed
> if
> * no other domains are using it.
> */
> #define IOCTL_GNTALLOC_DEALLOC_GREF \
> _IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
> struct ioctl_gntalloc_dealloc_gref {
> /* IN parameters */
> /* The offset returned in the map operation */
> uint64_t index;
> /* Number of references to unmap */
> uint32_t count;
> };
>
> #define IOCTL_GNTDEV_MAP_GRANT_REF \
> _IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
> struct ioctl_gntdev_map_grant_ref {
> /* IN parameters */
> /* The number of grants to be mapped. */
> uint32_t count;
> uint32_t pad;
> /* OUT parameters */
> /* The offset to be used on a subsequent call to mmap(). */
> uint64_t index;
> /* Variable IN parameter. */
> /* Array of grant references, of size @count. */
> struct ioctl_gntdev_grant_ref refs[1];
> };
> #define GNTDEV_MAP_WRITABLE 0x1
>
> #define IOCTL_GNTDEV_UNMAP_GRANT_REF \
> _IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
> struct ioctl_gntdev_unmap_grant_ref {
> /* IN parameters */
> /* The offset was returned by the corresponding map operation. */
> uint64_t index;
> /* The number of pages to be unmapped. */
> uint32_t count;
> uint32_t pad;
> };
>
> /*
> * Sets up an unmap notification within the page, so that the other side can
> do
> * cleanup if this side crashes. Required to implement cross-domain robust
> * mutexes or close notification on communication channels.
> *
> * Each mapped page only supports one notification; multiple calls referring
> to
> * the same page overwrite the previous notification. You must clear the
> * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
> * to occur.
> */
> #define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
> _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
> struct ioctl_gntdev_unmap_notify {
> /* IN parameters */
> /* Index of a byte in the page */
> uint64_t index;
> /* Action(s) to take on unmap */
> uint32_t action;
> /* Event channel to notify */
> uint32_t event_channel_port;
> };
>
> /* Clear (set to zero) the byte specified by index */
> #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
> /* Send an interrupt on the indicated event channel */
> #define UNMAP_NOTIFY_SEND_EVENT 0x2
>
> /*
> * Sets up an unmap notification within the page, so that the other side can
> do
> * cleanup if this side crashes. Required to implement cross-domain robust
> * mutexes or close notification on communication channels.
> *
> * Each mapped page only supports one notification; multiple calls referring
> to
> * the same page overwrite the previous notification. You must clear the
> * notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
> * to occur.
> */
> #define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
> _IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
> struct ioctl_gntalloc_unmap_notify {
> /* IN parameters */
> /* Index of a byte in the page */
> uint64_t index;
> /* Action(s) to take on unmap */
> uint32_t action;
> /* Event channel to notify */
> uint32_t event_channel_port;
> };
>
> /* Clear (set to zero) the byte specified by index */
> #define UNMAP_NOTIFY_CLEAR_BYTE 0x1
> /* Send an interrupt on the indicated event channel */
> #define UNMAP_NOTIFY_SEND_EVENT 0x2
>
> #ifndef offsetof
> #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
> #endif
>
>
> int a_fd;
> int d_fd;
>
> struct shr_page {
> uint64_t id;
> char buffer[64];
> uint8_t notifies[8];
> };
>
> struct data {
> struct shr_page* mem;
> int handle;
> } items[128];
>
> void sa(int id)
> {
> struct ioctl_gntalloc_alloc_gref arg = {
> .domid = id,
> .flags = GNTALLOC_FLAG_WRITABLE,
> .count = 1
> };
> int rv = ioctl(a_fd, IOCTL_GNTALLOC_ALLOC_GREF, &arg);
> if (rv) {
> printf("src-add error: %s (rv=%d)\n", strerror(errno), rv);
> return;
> }
> int i=0;
> while (items[i].mem) i++;
> items[i].mem = mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, a_fd,
> arg.index);
> if (items[i].mem == MAP_FAILED) {
> items[i].mem = 0;
> printf("mmap failed: SHOULD NOT HAPPEN\n");
> return;
> }
> items[i].handle = arg.index;
> printf("Created shared page with domain %d, grant #%d. Mapped locally
> at %d=%p\n",
> id, arg.gref_ids[0], arg.index, items[i].mem);
>
> items[i].mem->id = rand() | ((long)(getpid()) << 32);
> items[i].mem->notifies[0] = 1;
> struct ioctl_gntalloc_unmap_notify uarg = {
> .index = arg.index + offsetof(struct shr_page, notifies[0]),
> .action = UNMAP_NOTIFY_CLEAR_BYTE
> };
> rv = ioctl(a_fd, IOCTL_GNTALLOC_SET_UNMAP_NOTIFY, &uarg);
> if (rv)
> printf("gntalloc unmap notify error: %s (rv=%d)\n",
> strerror(errno), rv);
> }
>
> void sd(int ref) {
> struct ioctl_gntalloc_dealloc_gref arg = {
> .index = ref,
> .count = 1
> };
>
> int rv = ioctl(a_fd, IOCTL_GNTALLOC_DEALLOC_GREF, &arg);
> if (rv)
> printf("src-del error: %s (rv=%d)\n", strerror(errno), rv);
> else
> printf("Stopped offering grant at offset %d\n", ref);
> }
>
> void mm(int domid, int refid) {
> struct ioctl_gntdev_map_grant_ref arg = {
> .count = 1,
> .refs[0].domid = domid,
> .refs[0].ref = refid,
> };
> int rv = ioctl(d_fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg);
> if (rv) {
> printf("Could not map grant %d.%d: %s (rv=%d)\n", domid, refid,
> strerror(errno), rv);
> return;
> }
> int i=0,j=1;
> while (items[i].mem) i++;
> items[i].mem = mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, d_fd,
> arg.index);
> if (items[i].mem == MAP_FAILED) {
> items[i].mem = 0;
> printf("Could not map grant %d.%d: %s (map failed)\n", domid,
> refid, strerror(errno), rv);
> return;
> }
> items[i].handle = arg.index;
> printf("Mapped grant %d.%d as %d=%p\n", domid, refid, arg.index,
> items[i].mem);
>
> while (items[i].mem->notifies[j]) j++;
> items[i].mem->notifies[j] = 1;
> struct ioctl_gntalloc_unmap_notify uarg = {
> .index = arg.index + offsetof(struct shr_page, notifies[j]),
> .action = UNMAP_NOTIFY_CLEAR_BYTE
> };
> rv = ioctl(d_fd, IOCTL_GNTDEV_SET_UNMAP_NOTIFY, &uarg);
> if (rv)
> printf("gntdev unmap notify error: %s (rv=%d)\n",
> strerror(errno), rv);
> }
>
> void gu(int index) {
> struct ioctl_gntdev_unmap_grant_ref arg = {
> .index = index,
> .count = 1,
> };
> int rv = ioctl(d_fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &arg);
> if (rv)
> printf("gu error: %s (rv=%d)\n", strerror(errno), rv);
> else
> printf("Unhooked mapped grant at offset %d\n", index);
> }
>
> void mu(void* addr) {
> int i = 0;
> munmap(addr, 4096);
> while (i < 128)
> {
> if (items[i].mem == addr)
> items[i].mem = 0;
> i++;
> }
> printf("Unmapped page at %p\n", addr);
> }
>
> void show(char* word) {
> int i;
> int wlen = strlen(word);
> for(i=0; i < 128; i++) {
> if (!items[i].mem)
> continue;
> memmove(items[i].mem->buffer + wlen, items[i].mem->buffer, 63 -
> wlen);
> memcpy(items[i].mem->buffer, word, wlen);
> printf("%02d(%ld,%d): id %16lx n=%d%d%d%d%d%d%d%d b=%s\n",
> i, items[i].mem, items[i].handle, items[i].mem->id,
> items[i].mem->notifies[0], items[i].mem->notifies[1],
> items[i].mem->notifies[2], items[i].mem->notifies[3],
> items[i].mem->notifies[4], items[i].mem->notifies[5],
> items[i].mem->notifies[6], items[i].mem->notifies[7],
> items[i].mem->buffer);
> }
> printf("END\n");
> }
>
> int main(int argc, char** argv) {
> a_fd = open("/dev/xen/gntalloc", O_RDWR);
> d_fd = open("/dev/xen/gntdev", O_RDWR);
> printf(
> "add <domid> return gntref, address\n"
> "map <domid> <ref> return index, address\n"
> "adel <gntref> delete <add> internal\n"
> "ddel <index> delete <map> internal\n"
> "unmap <address> unmap memory\n"
> "show show all pages\n"
> "<word> append word to all mapped pages, show\n"
> " PID %x\n", getpid()
> );
> while (1) {
> char line[80];
> char word[80];
> long a, b;
> printf("\n> ");
> fflush(stdout);
> fgets(line, 80, stdin);
> sscanf(line, "%s %ld %ld", word, &a, &b);
> if (!strcmp(word, "add")) {
> sa(a);
> } else if (!strcmp(word, "map")) {
> mm(a, b);
> } else if (!strcmp(word, "adel")) {
> sd(a);
> } else if (!strcmp(word, "ddel")) {
> gu(a);
> } else if (!strcmp(word, "unmap")) {
> mu((void*)a);
> } else if (!strcmp(word, "show")) {
> show("");
> } else {
> show(word);
> }
> }
> }
> >
> > I really need some explanations .
> > Thanks!
> >
> >
> >
> > -------- Message original --------
> > Sujet: Fwd: [Xen-users] Shared memory between Dom0 and DomU
> > Date : Wed, 09 Mar 2011 15:12:06 +0100
> > De : MAYAP christine <christine.mayapkamga@xxxxxxxxxxx>
> > Pour : xen-devel@xxxxxxxxxxxxxxxxxxx, xen-users@xxxxxxxxxxxxxxxxxxx
> >
> >
> >
> > Hello
> >
> > While waiting for some help, i continued to google about this topic.
> > In fact, i want two distinct process (one on the Dom0 and the second
> > one on the DomU) to be able the read or write in a share memory.
> >
> > Many post are talking about granting permissions or grant table.
> >
> > I'm sorry if my question is a bit stupid. Where would i start to be
> > able the test those grant permission?
> > Should i need to write an external program or should i modify some
> > Xen source codes?
> >
> > I really have no idea about where to start.
> > I'll sincerely appreciate any idea. Even one stating where to start.
> >
> > Thanks in advance!
> >
> > -------- Message original --------
> > Sujet: [Xen-users] Shared memory between Dom0 and DomU
> > Date : Wed, 09 Mar 2011 13:07:19 +0100
> > De : MAYAP christine <christine.mayapkamga@xxxxxxxxxxx>
> > Pour : xen-devel@xxxxxxxxxxxxxxxxxxx, xen-users@xxxxxxxxxxxxxxxxxxx
> >
> >
> >
> > HI,
> >
> > I'm a newbie in using shared memory with Xen. I was usually unsing it
> > between process on a same Computer.
> >
> > Please, can i have some usefull links abour sharing memoru betwen Dom0
> > and DomU first and between DomU.
> >
> > I'm able to give more informations if needed!
> >
> > Cheers!
> >
> > --
> > MAYAP Christine
> > IRIT/ENSEEIHT
> > 2 rue Charles Camichel - BP 7122
> > 31071 Toulouse cedex 7
> >
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> >
>
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
>
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
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