Commit 38296400 authored by Marc-André Lureau's avatar Marc-André Lureau Committed by Paolo Bonzini
Browse files

hostmem-memfd: add checks before adding hostmem-memfd & properties 



Run some memfd-related checks before registering hostmem-memfd &
various properties. This will help libvirt to figure out what the host
is supposed to be capable of.

qemu_memfd_check() is changed to a less optimized version, since it is
used with various flags, it no longer caches the result.

Signed-off-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180906161415.8543-1-marcandre.lureau@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 7184de64

backends/hostmem-memfd.c

+19 −13
Original line number Diff line number Diff line
@@ -140,6 +140,7 @@ memfd_backend_class_init(ObjectClass *oc, void *data) 


    bc->alloc = memfd_backend_memory_alloc;



    if (qemu_memfd_check(MFD_HUGETLB)) {

        object_class_property_add_bool(oc, "hugetlb",

                                       memfd_backend_get_hugetlb,

                                       memfd_backend_set_hugetlb,
@@ -148,11 +149,14 @@ memfd_backend_class_init(ObjectClass *oc, void *data) 
                                  memfd_backend_get_hugetlbsize,

                                  memfd_backend_set_hugetlbsize,

                                  NULL, NULL, &error_abort);

    }

    if (qemu_memfd_check(MFD_ALLOW_SEALING)) {

        object_class_property_add_bool(oc, "seal",

                                       memfd_backend_get_seal,

                                       memfd_backend_set_seal,

                                       &error_abort);

    }

}



static const TypeInfo memfd_backend_info = {

    .name = TYPE_MEMORY_BACKEND_MEMFD,
@@ -164,7 +168,9 @@ static const TypeInfo memfd_backend_info = { 


static void register_types(void)

{

    if (qemu_memfd_check(0)) {

        type_register_static(&memfd_backend_info);

    }

}



type_init(register_types);

include/qemu/memfd.h

+17 −1
Original line number Diff line number Diff line
@@ -16,12 +16,28 @@ 
#define F_SEAL_WRITE    0x0008  /* prevent writes */

#endif



#ifndef MFD_CLOEXEC

#define MFD_CLOEXEC 0x0001U

#endif



#ifndef MFD_ALLOW_SEALING

#define MFD_ALLOW_SEALING 0x0002U

#endif



#ifndef MFD_HUGETLB

#define MFD_HUGETLB 0x0004U

#endif



#ifndef MFD_HUGE_SHIFT

#define MFD_HUGE_SHIFT 26

#endif



int qemu_memfd_create(const char *name, size_t size, bool hugetlb,

                      uint64_t hugetlbsize, unsigned int seals, Error **errp);

bool qemu_memfd_alloc_check(void);

void *qemu_memfd_alloc(const char *name, size_t size, unsigned int seals,

                       int *fd, Error **errp);

void qemu_memfd_free(void *ptr, size_t size, int fd);

bool qemu_memfd_check(void);

bool qemu_memfd_check(unsigned int flags);



#endif /* QEMU_MEMFD_H */

tests/vhost-user-test.c

+3 −3
Original line number Diff line number Diff line
@@ -169,7 +169,7 @@ static char *get_qemu_cmd(TestServer *s, 
                          int mem, enum test_memfd memfd, const char *mem_path,

                          const char *chr_opts, const char *extra)

{

    if (memfd == TEST_MEMFD_AUTO && qemu_memfd_check()) {

    if (memfd == TEST_MEMFD_AUTO && qemu_memfd_check(0)) {

        memfd = TEST_MEMFD_YES;

    }
@@ -903,7 +903,7 @@ static void test_multiqueue(void) 
    s->queues = 2;

    test_server_listen(s);



    if (qemu_memfd_check()) {

    if (qemu_memfd_check(0)) {

        cmd = g_strdup_printf(

            QEMU_CMD_MEMFD QEMU_CMD_CHR QEMU_CMD_NETDEV ",queues=%d "

            "-device virtio-net-pci,netdev=net0,mq=on,vectors=%d",
@@ -963,7 +963,7 @@ int main(int argc, char **argv) 
    /* run the main loop thread so the chardev may operate */

    thread = g_thread_new(NULL, thread_function, loop);



    if (qemu_memfd_check()) {

    if (qemu_memfd_check(0)) {

        qtest_add_data_func("/vhost-user/read-guest-mem/memfd",

                            GINT_TO_POINTER(TEST_MEMFD_YES),

                            test_read_guest_mem);

util/memfd.c

+6 −29
Original line number Diff line number Diff line
@@ -45,22 +45,6 @@ static int memfd_create(const char *name, unsigned int flags) 
}

#endif



#ifndef MFD_CLOEXEC

#define MFD_CLOEXEC 0x0001U

#endif



#ifndef MFD_ALLOW_SEALING

#define MFD_ALLOW_SEALING 0x0002U

#endif



#ifndef MFD_HUGETLB

#define MFD_HUGETLB 0x0004U

#endif



#ifndef MFD_HUGE_SHIFT

#define MFD_HUGE_SHIFT 26

#endif



int qemu_memfd_create(const char *name, size_t size, bool hugetlb,

                      uint64_t hugetlbsize, unsigned int seals, Error **errp)

{
@@ -201,23 +185,16 @@ bool qemu_memfd_alloc_check(void) 
 *

 * Check if host supports memfd.

 */

bool qemu_memfd_check(void)

bool qemu_memfd_check(unsigned int flags)

{

#ifdef CONFIG_LINUX

    static int memfd_check = MEMFD_TODO;

    int mfd = memfd_create("test", flags);



    if (memfd_check == MEMFD_TODO) {

        int mfd = memfd_create("test", 0);

    if (mfd >= 0) {

            memfd_check = MEMFD_OK;

        close(mfd);

        } else {

            memfd_check = MEMFD_KO;

        }

        return true;

    }

#endif



    return memfd_check == MEMFD_OK;

#else

    return false;

#endif

}