From 6f81bd1a3ec3b8c06ec614f09eac688c6053f412 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 19 Sep 2024 14:46:24 +0100 Subject: util/userfaultfd: Return -errno on error Convert (the currently unused) uffd_wakeup, uffd_copy_page and uffd_zero_page to return -errno on error rather than -1. That will make it easier to reuse in postcopy. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Peter Xu Link: https://lore.kernel.org/r/20240919134626.166183-6-dave@treblig.org Signed-off-by: Peter Xu --- util/userfaultfd.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) (limited to 'util/userfaultfd.c') diff --git a/util/userfaultfd.c b/util/userfaultfd.c index 1b2fa949d4..518d5c3586 100644 --- a/util/userfaultfd.c +++ b/util/userfaultfd.c @@ -240,7 +240,7 @@ int uffd_change_protection(int uffd_fd, void *addr, uint64_t length, * Copy range of source pages to the destination to resolve * missing page fault somewhere in the destination range. * - * Returns 0 on success, negative value in case of an error + * Returns 0 on success, -errno in case of an error * * @uffd_fd: UFFD file descriptor * @dst_addr: destination base address @@ -259,10 +259,11 @@ int uffd_copy_page(int uffd_fd, void *dst_addr, void *src_addr, uffd_copy.mode = dont_wake ? UFFDIO_COPY_MODE_DONTWAKE : 0; if (ioctl(uffd_fd, UFFDIO_COPY, &uffd_copy)) { + int e = errno; error_report("uffd_copy_page() failed: dst_addr=%p src_addr=%p length=%" PRIu64 " mode=%" PRIx64 " errno=%i", dst_addr, src_addr, - length, (uint64_t) uffd_copy.mode, errno); - return -1; + length, (uint64_t) uffd_copy.mode, e); + return -e; } return 0; @@ -273,7 +274,7 @@ int uffd_copy_page(int uffd_fd, void *dst_addr, void *src_addr, * * Fill range pages with zeroes to resolve missing page fault within the range. * - * Returns 0 on success, negative value in case of an error + * Returns 0 on success, -errno in case of an error * * @uffd_fd: UFFD file descriptor * @addr: base address @@ -289,10 +290,11 @@ int uffd_zero_page(int uffd_fd, void *addr, uint64_t length, bool dont_wake) uffd_zeropage.mode = dont_wake ? UFFDIO_ZEROPAGE_MODE_DONTWAKE : 0; if (ioctl(uffd_fd, UFFDIO_ZEROPAGE, &uffd_zeropage)) { + int e = errno; error_report("uffd_zero_page() failed: addr=%p length=%" PRIu64 " mode=%" PRIx64 " errno=%i", addr, length, - (uint64_t) uffd_zeropage.mode, errno); - return -1; + (uint64_t) uffd_zeropage.mode, e); + return -e; } return 0; @@ -306,7 +308,7 @@ int uffd_zero_page(int uffd_fd, void *addr, uint64_t length, bool dont_wake) * via UFFD-IO IOCTLs with MODE_DONTWAKE flag set, then after that all waits * for the whole memory range are satisfied in a single call to uffd_wakeup(). * - * Returns 0 on success, negative value in case of an error + * Returns 0 on success, -errno in case of an error * * @uffd_fd: UFFD file descriptor * @addr: base address @@ -320,9 +322,10 @@ int uffd_wakeup(int uffd_fd, void *addr, uint64_t length) uffd_range.len = length; if (ioctl(uffd_fd, UFFDIO_WAKE, &uffd_range)) { + int e = errno; error_report("uffd_wakeup() failed: addr=%p length=%" PRIu64 " errno=%i", - addr, length, errno); - return -1; + addr, length, e); + return -e; } return 0; -- cgit 1.4.1 From ccf6b78275816c9dec84d3a40e9aa3b6ba6ebc06 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 19 Sep 2024 14:46:26 +0100 Subject: util/userfaultfd: Remove unused uffd_poll_events uffd_poll_events has been unused since it was added; it's also just a wrapper around a plain old poll call, so doesn't add anything. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Peter Xu Link: https://lore.kernel.org/r/20240919134626.166183-8-dave@treblig.org Signed-off-by: Peter Xu --- include/qemu/userfaultfd.h | 1 - util/userfaultfd.c | 28 ---------------------------- 2 files changed, 29 deletions(-) (limited to 'util/userfaultfd.c') diff --git a/include/qemu/userfaultfd.h b/include/qemu/userfaultfd.h index 18a4314212..a1979308d7 100644 --- a/include/qemu/userfaultfd.h +++ b/include/qemu/userfaultfd.h @@ -39,7 +39,6 @@ int uffd_copy_page(int uffd_fd, void *dst_addr, void *src_addr, int uffd_zero_page(int uffd_fd, void *addr, uint64_t length, bool dont_wake); int uffd_wakeup(int uffd_fd, void *addr, uint64_t length); int uffd_read_events(int uffd_fd, struct uffd_msg *msgs, int count); -bool uffd_poll_events(int uffd_fd, int tmo); #endif /* CONFIG_LINUX */ diff --git a/util/userfaultfd.c b/util/userfaultfd.c index 518d5c3586..2396104f23 100644 --- a/util/userfaultfd.c +++ b/util/userfaultfd.c @@ -358,31 +358,3 @@ int uffd_read_events(int uffd_fd, struct uffd_msg *msgs, int count) return (int) (res / sizeof(struct uffd_msg)); } - -/** - * uffd_poll_events: poll UFFD file descriptor for read - * - * Returns true if events are available for read, false otherwise - * - * @uffd_fd: UFFD file descriptor - * @tmo: timeout value - */ -bool uffd_poll_events(int uffd_fd, int tmo) -{ - int res; - struct pollfd poll_fd = { .fd = uffd_fd, .events = POLLIN, .revents = 0 }; - - do { - res = poll(&poll_fd, 1, tmo); - } while (res < 0 && errno == EINTR); - - if (res == 0) { - return false; - } - if (res < 0) { - error_report("uffd_poll_events() failed: errno=%i", errno); - return false; - } - - return (poll_fd.revents & POLLIN) != 0; -} -- cgit 1.4.1