From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53983) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4o6P-0007r6-Id for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:28:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z4o6O-0001MV-DP for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:28:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60197) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4o6O-0001MP-6s for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:28:20 -0400 From: "Dr. David Alan Gilbert (git)" Date: Tue, 16 Jun 2015 11:26:46 +0100 Message-Id: <1434450415-11339-34-git-send-email-dgilbert@redhat.com> In-Reply-To: <1434450415-11339-1-git-send-email-dgilbert@redhat.com> References: <1434450415-11339-1-git-send-email-dgilbert@redhat.com> Subject: [Qemu-devel] [PATCH v7 33/42] postcopy_ram.c: place_page and helpers List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, quintela@redhat.com, liang.z.li@intel.com, luis@cs.umu.se, amit.shah@redhat.com, pbonzini@redhat.com, david@gibson.dropbear.id.au From: "Dr. David Alan Gilbert" postcopy_place_page (etc) provide a way for postcopy to place a page into guests memory atomically (using the copy ioctl on the ufd). Signed-off-by: Dr. David Alan Gilbert --- include/migration/migration.h | 1 + include/migration/postcopy-ram.h | 16 ++++++++ migration/postcopy-ram.c | 87 ++++++++++++++++++++++++++++++++++++++++ trace-events | 1 + 4 files changed, 105 insertions(+) diff --git a/include/migration/migration.h b/include/migration/migration.h index 20d1b39..8d2e5c8 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -79,6 +79,7 @@ struct MigrationIncomingState { QEMUFile *return_path; QemuMutex rp_mutex; /* We send replies from multiple threads */ PostcopyState postcopy_state; + void *postcopy_tmp_page; /* See savevm.c */ LoadStateEntry_Head loadvm_handlers; diff --git a/include/migration/postcopy-ram.h b/include/migration/postcopy-ram.h index 8a8616b..bac79c5 100644 --- a/include/migration/postcopy-ram.h +++ b/include/migration/postcopy-ram.h @@ -69,4 +69,20 @@ void postcopy_discard_send_range(MigrationState *ms, PostcopyDiscardState *pds, void postcopy_discard_send_finish(MigrationState *ms, PostcopyDiscardState *pds); +/* + * Place a page (from) at (host) efficiently + * There are restrictions on how 'from' must be mapped, in general best + * to use other postcopy_ routines to allocate. + * returns 0 on success + */ +int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, + bool all_zero); + +/* + * Allocate a page of memory that can be mapped at a later point in time + * using postcopy_place_page + * Returns: Pointer to allocated page + */ +void *postcopy_get_tmp_page(MigrationIncomingState *mis); + #endif diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 7158d08..6345480 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -279,6 +279,10 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) return -1; } + if (mis->postcopy_tmp_page) { + munmap(mis->postcopy_tmp_page, getpagesize()); + mis->postcopy_tmp_page = NULL; + } return 0; } @@ -345,6 +349,77 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis) return 0; } +/* + * Place a host page (from) at (host) atomically + * all_zero: Hint that the page being placed is 0 throughout + * returns 0 on success + */ +int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, + bool all_zero) +{ + if (!all_zero) { + struct uffdio_copy copy_struct; + + copy_struct.dst = (uint64_t)(uintptr_t)host; + copy_struct.src = (uint64_t)(uintptr_t)from; + copy_struct.len = getpagesize(); + copy_struct.mode = 0; + + /* copy also acks to the kernel waking the stalled thread up + * TODO: We can inhibit that ack and only do it if it was requested + * which would be slightly cheaper, but we'd have to be careful + * of the order of updating our page state. + */ + if (ioctl(mis->userfault_fd, UFFDIO_COPY, ©_struct)) { + int e = errno; + error_report("%s: %s copy host: %p from: %p", + __func__, strerror(e), host, from); + + return -e; + } + } else { + struct uffdio_zeropage zero_struct; + + zero_struct.range.start = (uint64_t)(uintptr_t)host; + zero_struct.range.len = getpagesize(); + zero_struct.mode = 0; + + if (ioctl(mis->userfault_fd, UFFDIO_ZEROPAGE, &zero_struct)) { + int e = errno; + error_report("%s: %s zero host: %p from: %p", + __func__, strerror(e), host, from); + + return -e; + } + } + + trace_postcopy_place_page(host, all_zero); + return 0; +} + +/* + * Returns a target page of memory that can be mapped at a later point in time + * using postcopy_place_page + * The same address is used repeatedly, postcopy_place_page just takes the + * backing page away. + * Returns: Pointer to allocated page + * + */ +void *postcopy_get_tmp_page(MigrationIncomingState *mis) +{ + if (!mis->postcopy_tmp_page) { + mis->postcopy_tmp_page = mmap(NULL, getpagesize(), + PROT_READ | PROT_WRITE, MAP_PRIVATE | + MAP_ANONYMOUS, -1, 0); + if (!mis->postcopy_tmp_page) { + error_report("%s: %s", __func__, strerror(errno)); + return NULL; + } + } + + return mis->postcopy_tmp_page; +} + #else /* No target OS support, stubs just fail */ bool postcopy_ram_supported_by_host(void) @@ -374,6 +449,18 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis) { assert(0); } + +int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, + bool all_zero) +{ + assert(0); +} + +void *postcopy_get_tmp_page(MigrationIncomingState *mis) +{ + assert(0); +} + #endif /* ------------------------------------------------------------------------- */ diff --git a/trace-events b/trace-events index cb707c7..d9c5a51 100644 --- a/trace-events +++ b/trace-events @@ -1515,6 +1515,7 @@ postcopy_discard_send_finish(const char *ramblock, int nwords, int ncmds) "%s ma postcopy_cleanup_area(const char *ramblock, void *host_addr, size_t offset, size_t length) "%s: %p offset=%zx length=%zx" postcopy_ram_discard_range(void *start, void *end) "%p,%p" postcopy_init_area(const char *ramblock, void *host_addr, size_t offset, size_t length) "%s: %p offset=%zx length=%zx" +postcopy_place_page(void *host_addr, bool all_zero) "host=%p all_zero=%d" # kvm-all.c kvm_ioctl(int type, void *arg) "type 0x%x, arg %p" -- 2.4.3