Merge tag 'pull-misc-20240821' of https://gitlab.com/rth7680/qemu into staging

target/i386: Fix carry flag for BLSI
target/i386: Fix tss access size in switch_tss_ra
linux-user: Handle short reads in mmap_h_gt_g
bsd-user: Handle short reads in mmap_h_gt_g

# -----BEGIN PGP SIGNATURE-----
#
# iQFRBAABCgA7FiEEekgeeIaLTbaoWgXAZN846K9+IV8FAmbFTzUdHHJpY2hhcmQu
# aGVuZGVyc29uQGxpbmFyby5vcmcACgkQZN846K9+IV/9+Qf9GiXgmZU51Rk9LaNz
# zlaUPIJy/ER+lCpkaeIqMzJ3EysuWa5tZFOrg21rqmfMr19AIuPSRmCFXuwkF6s+
# DnCiToloM/EvczmVQALE/KhOOm0dwvoAwSFBFTCPfg/IKjb9OcOWHGJVSgFV/1u6
# vrTqUc6xny6QhMjTuVWziE/VAH0V9wRjToii2qN9k/5e2oF1hzDGjHx7T9d//4j5
# hbRyzH0luexvob7JCpxHDELlarkoyR5a7cJQHTj0VTfmR5g6yEMLn+z7ocBcUF09
# pJzcRu2BHUYjzQgV6wqdj5aw8N26c+e8pm1XIA8S1CwBnLRnkuuCKKD7I0tdYvFA
# VgDntQ==
# =XyeR
# -----END PGP SIGNATURE-----
# gpg: Signature made Wed 21 Aug 2024 12:21:41 PM AEST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [ultimate]

* tag 'pull-misc-20240821' of https://gitlab.com/rth7680/qemu:
  target/i386: Fix tss access size in switch_tss_ra
  target/i386: Fix carry flag for BLSI
  target/i386: Split out gen_prepare_val_nz
  bsd-user: Handle short reads in mmap_h_gt_g
  linux-user: Handle short reads in mmap_h_gt_g

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 38 insertions, 6 deletions

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 6418e811f6..e4bf5d5f39 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -284,6 +284,40 @@ static int do_munmap(void *addr, size_t len)
 }
 
 /*
+ * Perform a pread on behalf of target_mmap.  We can reach EOF, we can be
+ * interrupted by signals, and in general there's no good error return path.
+ * If @zero, zero the rest of the block at EOF.
+ * Return true on success.
+ */
+static bool mmap_pread(int fd, void *p, size_t len, off_t offset, bool zero)
+{
+    while (1) {
+        ssize_t r = pread(fd, p, len, offset);
+
+        if (likely(r == len)) {
+            /* Complete */
+            return true;
+        }
+        if (r == 0) {
+            /* EOF */
+            if (zero) {
+                memset(p, 0, len);
+            }
+            return true;
+        }
+        if (r > 0) {
+            /* Short read */
+            p += r;
+            len -= r;
+            offset += r;
+        } else if (errno != EINTR) {
+            /* Error */
+            return false;
+        }
+    }
+}
+
+/*
  * Map an incomplete host page.
  *
  * Here be dragons.  This case will not work if there is an existing
@@ -357,10 +391,9 @@ static bool mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong last,
     /* Read or zero the new guest pages. */
     if (flags & MAP_ANONYMOUS) {
         memset(g2h_untagged(start), 0, last - start + 1);
-    } else {
-        if (pread(fd, g2h_untagged(start), last - start + 1, offset) == -1) {
-            return false;
-        }
+    } else if (!mmap_pread(fd, g2h_untagged(start), last - start + 1,
+                           offset, true)) {
+        return false;
     }
 
     /* Put final protection */
@@ -853,8 +886,7 @@ static abi_long mmap_h_gt_g(abi_ulong start, abi_ulong len,
     }
 
     if (misaligned_offset) {
-        /* TODO: The read could be short. */
-        if (pread(fd, p, host_len, offset + real_start - start) != host_len) {
+        if (!mmap_pread(fd, p, host_len, offset + real_start - start, false)) {
             do_munmap(p, host_len);
             return -1;
         }