* [PATCH v1 01/10] tests/guest-debug: catch hanging guests
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-21 14:06 ` Philippe Mathieu-Daudé
2020-05-13 17:51 ` [PATCH v1 02/10] travis.yml: Improve the --disable-tcg test on s390x Alex Bennée
` (8 subsequent siblings)
9 siblings, 1 reply; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel; +Cc: Alex Bennée
If gdb never actually connected with the guest we need to catch that
and clean-up after ourselves.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200512104338.27365-1-alex.bennee@linaro.org>
---
tests/guest-debug/run-test.py | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tests/guest-debug/run-test.py b/tests/guest-debug/run-test.py
index d9af9573b9e..71c55690546 100755
--- a/tests/guest-debug/run-test.py
+++ b/tests/guest-debug/run-test.py
@@ -80,4 +80,10 @@ if __name__ == '__main__':
print("GDB crashed? SKIPPING")
exit(0)
+ try:
+ inferior.wait(2)
+ except subprocess.TimeoutExpired:
+ print("GDB never connected? Killed guest")
+ inferior.kill()
+
exit(result)
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* Re: [PATCH v1 01/10] tests/guest-debug: catch hanging guests
2020-05-13 17:51 ` [PATCH v1 01/10] tests/guest-debug: catch hanging guests Alex Bennée
@ 2020-05-21 14:06 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 19+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-05-21 14:06 UTC (permalink / raw)
To: Alex Bennée, qemu-devel
On 5/13/20 7:51 PM, Alex Bennée wrote:
> If gdb never actually connected with the guest we need to catch that
> and clean-up after ourselves.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Message-Id: <20200512104338.27365-1-alex.bennee@linaro.org>
> ---
> tests/guest-debug/run-test.py | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tests/guest-debug/run-test.py b/tests/guest-debug/run-test.py
> index d9af9573b9e..71c55690546 100755
> --- a/tests/guest-debug/run-test.py
> +++ b/tests/guest-debug/run-test.py
> @@ -80,4 +80,10 @@ if __name__ == '__main__':
> print("GDB crashed? SKIPPING")
> exit(0)
>
> + try:
> + inferior.wait(2)
> + except subprocess.TimeoutExpired:
> + print("GDB never connected? Killed guest")
Maybe "Killing guest"?
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> + inferior.kill()
> +
> exit(result)
>
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH v1 02/10] travis.yml: Improve the --disable-tcg test on s390x
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
2020-05-13 17:51 ` [PATCH v1 01/10] tests/guest-debug: catch hanging guests Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-13 17:51 ` [PATCH v1 03/10] tests/docker: Kludge <linux/swab.h> breakage by pinning linux-libc-dev Alex Bennée
` (7 subsequent siblings)
9 siblings, 0 replies; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel
Cc: Fam Zheng, Thomas Huth, Philippe Mathieu-Daudé,
Cornelia Huck, open list:S390 general arch...,
Alex Bennée
From: Thomas Huth <thuth@redhat.com>
Since the s390x containers do not allow KVM, we only compile-test
the --disable-tcg build on s390x and do not run the qtests. Thus,
it does not make sense to install genisoimage here, and it also does
not make sense to build the s390-ccw.img here again - it is simply
not used without the qtests.
On the other hand, if we do not build the s390-ccw.img anymore, we
can also compile with Clang - so let's use that compiler here to
get some additional test coverage.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200512133849.10624-1-thuth@redhat.com>
---
.travis.yml | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/.travis.yml b/.travis.yml
index fe708792ca2..1ec8a7b4657 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -502,9 +502,10 @@ jobs:
$(exit $BUILD_RC);
fi
- - name: "[s390x] GCC check (KVM)"
+ - name: "[s390x] Clang (disable-tcg)"
arch: s390x
dist: bionic
+ compiler: clang
addons:
apt_packages:
- libaio-dev
@@ -528,21 +529,10 @@ jobs:
- libusb-1.0-0-dev
- libvdeplug-dev
- libvte-2.91-dev
- # Tests dependencies
- - genisoimage
env:
- TEST_CMD="make check-unit"
- - CONFIG="--disable-containers --disable-tcg --enable-kvm --disable-tools"
- script:
- - ( cd ${SRC_DIR} ; git submodule update --init roms/SLOF )
- - BUILD_RC=0 && make -j${JOBS} || BUILD_RC=$?
- - |
- if [ "$BUILD_RC" -eq 0 ] ; then
- mv pc-bios/s390-ccw/*.img pc-bios/ ;
- ${TEST_CMD} ;
- else
- $(exit $BUILD_RC);
- fi
+ - CONFIG="--disable-containers --disable-tcg --enable-kvm
+ --disable-tools --host-cc=clang --cxx=clang++"
# Release builds
# The make-release script expect a QEMU version, so our tag must start with a 'v'.
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* [PATCH v1 03/10] tests/docker: Kludge <linux/swab.h> breakage by pinning linux-libc-dev
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
2020-05-13 17:51 ` [PATCH v1 01/10] tests/guest-debug: catch hanging guests Alex Bennée
2020-05-13 17:51 ` [PATCH v1 02/10] travis.yml: Improve the --disable-tcg test on s390x Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-13 17:51 ` [PATCH v1 04/10] linux-user: completely re-write init_guest_space Alex Bennée
` (6 subsequent siblings)
9 siblings, 0 replies; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel
Cc: Fam Zheng, Alex Bennée, Philippe Mathieu-Daudé,
Christian Borntraeger, Philippe Mathieu-Daudé,
Salvatore Bonaccorso
From: Philippe Mathieu-Daudé <f4bug@amsat.org>
Linux kernel commit d5767057c9a [1] aimed to fix an issue with the
swab() declaration, but doing so it introduced the BITS_PER_LONG
definition, without using the kernel __ prefix, leading to odd
failures in userland code using kernel uapi headers, such:
CC block/file-posix.o
In file included from include/qemu/timer.h:4,
from include/qemu/timed-average.h:29,
from include/block/accounting.h:28,
from include/block/block_int.h:27,
from block/file-posix.c:30:
/usr/include/linux/swab.h: In function `__swab':
include/qemu/bitops.h:20:34: error: "sizeof" is not defined, evaluates to 0 [-Werror=undef]
20 | #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE)
| ^~~~~~
include/qemu/bitops.h:20:41: error: missing binary operator before token "("
20 | #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE)
| ^
cc1: all warnings being treated as errors
make: *** [rules.mak:69: block/file-posix.o] Error 1
The issue has been fixed in Linux kernel commit 467d12f5c78 [2].
Some distributions already backported the first commit, but still
lack the second one.
This is the case for Debian Buster.
The linux-libc-dev package contains the Linux kernel headers.
Kernel commit d5767057c9a has been backported in package
commit 1fb0eb7956 "Update to 4.19.116" [3], see debian/changelog:
+linux (4.19.116-1) UNRELEASED; urgency=medium
...
+ - uapi: rename ext2_swab() to swab() and share globally in swab.h
The previous released update before it is debian/4.19.98-1,
released as debian/4.19.98-1+deb10u1.
We can find this package in the Debian snapshot archives,
luckily archived on 2020-04-28 21:20:54 (see [4]).
QEMU use Debian based Docker images for most of its cross-builds,
which are tested by our Shippable CI jobs. The current broken
package makes most of our CI red. We can kludge this by using the
latest package released before the breakage. Do so by pinning
the package version (apt hold), and using the snapshot archives,
similar to commit b4048a7cd1.
We'll revert once the fix is backported on Debian.
Reference to commits:
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d5767057c9a
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=467d12f5c78
[3] https://salsa.debian.org/kernel-team/linux/-/commit/1fb0eb7956
[4] http://snapshot.debian.org/package/linux/4.19.98-1%2Bdeb10u1/#linux-libc-dev_4.19.98-1:2b:deb10u1
Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
[AJB: dropped pinning]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200513120147.21443-1-f4bug@amsat.org>
---
tests/docker/dockerfiles/debian10.docker | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/tests/docker/dockerfiles/debian10.docker b/tests/docker/dockerfiles/debian10.docker
index 0769700a416..58b23117240 100644
--- a/tests/docker/dockerfiles/debian10.docker
+++ b/tests/docker/dockerfiles/debian10.docker
@@ -9,6 +9,15 @@
#
FROM debian:buster-slim
+ # Use a snapshot known to work (see http://snapshot.debian.org/#Usage)
+ENV DEBIAN_SNAPSHOT_DATE "20200428T212054Z"
+RUN sed -i \
+ "s%^deb \(https\?://\)deb.debian.org/debian/\? \(.*\)%deb [check-valid-until=no] \1snapshot.debian.org/archive/debian/${DEBIAN_SNAPSHOT_DATE} \2%" \
+ /etc/apt/sources.list
+RUN sed -i \
+ "s%^deb \(https\?://\)security.debian.org/debian-security/\? \(.*\)%deb [check-valid-until=no] \1snapshot.debian.org/archive/debian-security/${DEBIAN_SNAPSHOT_DATE} \2%" \
+ /etc/apt/sources.list
+
# Duplicate deb line as deb-src
RUN cat /etc/apt/sources.list | sed "s/^deb\ /deb-src /" >> /etc/apt/sources.list
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* [PATCH v1 04/10] linux-user: completely re-write init_guest_space
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
` (2 preceding siblings ...)
2020-05-13 17:51 ` [PATCH v1 03/10] tests/docker: Kludge <linux/swab.h> breakage by pinning linux-libc-dev Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-21 4:43 ` Thomas Huth
2020-05-13 17:51 ` [PATCH v1 05/10] exec/cpu-all: Use bool for have_guest_base Alex Bennée
` (5 subsequent siblings)
9 siblings, 1 reply; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel; +Cc: Riku Voipio, Alex Bennée, Laurent Vivier
First we ensure all guest space initialisation logic comes through
probe_guest_base once we understand the nature of the binary we are
loading. The convoluted init_guest_space routine is removed and
replaced with a number of pgb_* helpers which are called depending on
what requirements we have when loading the binary.
We first try to do what is requested by the host. Failing that we try
and satisfy the guest requested base address. If all those options
fail we fall back to finding a space in the memory map using our
recently written read_self_maps() helper.
There are some additional complications we try and take into account
when looking for holes in the address space. We try not to go directly
after the system brk() space so there is space for a little growth. We
also don't want to have to use negative offsets which would result in
slightly less efficient code on x86 when it's unable to use the
segment offset register.
Less mind-binding gotos and hopefully clearer logic throughout.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Laurent Vivier <laurent@vivier.eu>
---
v3
- include rth updates that
- split probe_guest_base into multiple functions
- more heuristics on gap finding
v4
- whitespace fix
- added Laurent's a-b
---
linux-user/qemu.h | 31 ++-
linux-user/elfload.c | 503 +++++++++++++++++++++---------------------
linux-user/flatload.c | 6 +
linux-user/main.c | 23 +-
4 files changed, 277 insertions(+), 286 deletions(-)
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 792c74290f8..ce902f5132a 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -219,18 +219,27 @@ void init_qemu_uname_release(void);
void fork_start(void);
void fork_end(int child);
-/* Creates the initial guest address space in the host memory space using
- * the given host start address hint and size. The guest_start parameter
- * specifies the start address of the guest space. guest_base will be the
- * difference between the host start address computed by this function and
- * guest_start. If fixed is specified, then the mapped address space must
- * start at host_start. The real start address of the mapped memory space is
- * returned or -1 if there was an error.
+/**
+ * probe_guest_base:
+ * @image_name: the executable being loaded
+ * @loaddr: the lowest fixed address in the executable
+ * @hiaddr: the highest fixed address in the executable
+ *
+ * Creates the initial guest address space in the host memory space.
+ *
+ * If @loaddr == 0, then no address in the executable is fixed,
+ * i.e. it is fully relocatable. In that case @hiaddr is the size
+ * of the executable.
+ *
+ * This function will not return if a valid value for guest_base
+ * cannot be chosen. On return, the executable loader can expect
+ *
+ * target_mmap(loaddr, hiaddr - loaddr, ...)
+ *
+ * to succeed.
*/
-unsigned long init_guest_space(unsigned long host_start,
- unsigned long host_size,
- unsigned long guest_start,
- bool fixed);
+void probe_guest_base(const char *image_name,
+ abi_ulong loaddr, abi_ulong hiaddr);
#include "qemu/log.h"
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 619c054cc48..01a9323a637 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -11,6 +11,7 @@
#include "qemu/queue.h"
#include "qemu/guest-random.h"
#include "qemu/units.h"
+#include "qemu/selfmap.h"
#ifdef _ARCH_PPC64
#undef ARCH_DLINFO
@@ -382,68 +383,30 @@ enum {
/* The commpage only exists for 32 bit kernels */
-/* Return 1 if the proposed guest space is suitable for the guest.
- * Return 0 if the proposed guest space isn't suitable, but another
- * address space should be tried.
- * Return -1 if there is no way the proposed guest space can be
- * valid regardless of the base.
- * The guest code may leave a page mapped and populate it if the
- * address is suitable.
- */
-static int init_guest_commpage(unsigned long guest_base,
- unsigned long guest_size)
-{
- unsigned long real_start, test_page_addr;
-
- /* We need to check that we can force a fault on access to the
- * commpage at 0xffff0fxx
- */
- test_page_addr = guest_base + (0xffff0f00 & qemu_host_page_mask);
-
- /* If the commpage lies within the already allocated guest space,
- * then there is no way we can allocate it.
- *
- * You may be thinking that that this check is redundant because
- * we already validated the guest size against MAX_RESERVED_VA;
- * but if qemu_host_page_mask is unusually large, then
- * test_page_addr may be lower.
- */
- if (test_page_addr >= guest_base
- && test_page_addr < (guest_base + guest_size)) {
- return -1;
- }
+#define ARM_COMMPAGE (intptr_t)0xffff0f00u
- /* Note it needs to be writeable to let us initialise it */
- real_start = (unsigned long)
- mmap((void *)test_page_addr, qemu_host_page_size,
- PROT_READ | PROT_WRITE,
- MAP_ANONYMOUS | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+static bool init_guest_commpage(void)
+{
+ void *want = g2h(ARM_COMMPAGE & -qemu_host_page_size);
+ void *addr = mmap(want, qemu_host_page_size, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
- /* If we can't map it then try another address */
- if (real_start == -1ul) {
- return 0;
+ if (addr == MAP_FAILED) {
+ perror("Allocating guest commpage");
+ exit(EXIT_FAILURE);
}
-
- if (real_start != test_page_addr) {
- /* OS didn't put the page where we asked - unmap and reject */
- munmap((void *)real_start, qemu_host_page_size);
- return 0;
+ if (addr != want) {
+ return false;
}
- /* Leave the page mapped
- * Populate it (mmap should have left it all 0'd)
- */
-
- /* Kernel helper versions */
- __put_user(5, (uint32_t *)g2h(0xffff0ffcul));
+ /* Set kernel helper versions; rest of page is 0. */
+ __put_user(5, (uint32_t *)g2h(0xffff0ffcu));
- /* Now it's populated make it RO */
- if (mprotect((void *)test_page_addr, qemu_host_page_size, PROT_READ)) {
+ if (mprotect(addr, qemu_host_page_size, PROT_READ)) {
perror("Protecting guest commpage");
- exit(-1);
+ exit(EXIT_FAILURE);
}
-
- return 1; /* All good */
+ return true;
}
#define ELF_HWCAP get_elf_hwcap()
@@ -2075,239 +2038,267 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
return sp;
}
-unsigned long init_guest_space(unsigned long host_start,
- unsigned long host_size,
- unsigned long guest_start,
- bool fixed)
-{
- /* In order to use host shmat, we must be able to honor SHMLBA. */
- unsigned long align = MAX(SHMLBA, qemu_host_page_size);
- unsigned long current_start, aligned_start;
- int flags;
-
- assert(host_start || host_size);
-
- /* If just a starting address is given, then just verify that
- * address. */
- if (host_start && !host_size) {
-#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
- if (init_guest_commpage(host_start, host_size) != 1) {
- return (unsigned long)-1;
- }
+#ifndef ARM_COMMPAGE
+#define ARM_COMMPAGE 0
+#define init_guest_commpage() true
#endif
- return host_start;
- }
- /* Setup the initial flags and start address. */
- current_start = host_start & -align;
- flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
- if (fixed) {
- flags |= MAP_FIXED;
- }
+static void pgb_fail_in_use(const char *image_name)
+{
+ error_report("%s: requires virtual address space that is in use "
+ "(omit the -B option or choose a different value)",
+ image_name);
+ exit(EXIT_FAILURE);
+}
- /* Otherwise, a non-zero size region of memory needs to be mapped
- * and validated. */
+static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr,
+ abi_ulong guest_hiaddr, long align)
+{
+ const int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
+ void *addr, *test;
-#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
- /* On 32-bit ARM, we need to map not just the usable memory, but
- * also the commpage. Try to find a suitable place by allocating
- * a big chunk for all of it. If host_start, then the naive
- * strategy probably does good enough.
- */
- if (!host_start) {
- unsigned long guest_full_size, host_full_size, real_start;
-
- guest_full_size =
- (0xffff0f00 & qemu_host_page_mask) + qemu_host_page_size;
- host_full_size = guest_full_size - guest_start;
- real_start = (unsigned long)
- mmap(NULL, host_full_size, PROT_NONE, flags, -1, 0);
- if (real_start == (unsigned long)-1) {
- if (host_size < host_full_size - qemu_host_page_size) {
- /* We failed to map a continous segment, but we're
- * allowed to have a gap between the usable memory and
- * the commpage where other things can be mapped.
- * This sparseness gives us more flexibility to find
- * an address range.
- */
- goto naive;
- }
- return (unsigned long)-1;
+ if (!QEMU_IS_ALIGNED(guest_base, align)) {
+ fprintf(stderr, "Requested guest base 0x%lx does not satisfy "
+ "host minimum alignment (0x%lx)\n",
+ guest_base, align);
+ exit(EXIT_FAILURE);
+ }
+
+ /* Sanity check the guest binary. */
+ if (reserved_va) {
+ if (guest_hiaddr > reserved_va) {
+ error_report("%s: requires more than reserved virtual "
+ "address space (0x%" PRIx64 " > 0x%lx)",
+ image_name, (uint64_t)guest_hiaddr, reserved_va);
+ exit(EXIT_FAILURE);
}
- munmap((void *)real_start, host_full_size);
- if (real_start & (align - 1)) {
- /* The same thing again, but with extra
- * so that we can shift around alignment.
- */
- unsigned long real_size = host_full_size + qemu_host_page_size;
- real_start = (unsigned long)
- mmap(NULL, real_size, PROT_NONE, flags, -1, 0);
- if (real_start == (unsigned long)-1) {
- if (host_size < host_full_size - qemu_host_page_size) {
- goto naive;
- }
- return (unsigned long)-1;
- }
- munmap((void *)real_start, real_size);
- real_start = ROUND_UP(real_start, align);
+ } else {
+ if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
+ error_report("%s: requires more virtual address space "
+ "than the host can provide (0x%" PRIx64 ")",
+ image_name, (uint64_t)guest_hiaddr - guest_base);
+ exit(EXIT_FAILURE);
}
- current_start = real_start;
}
- naive:
-#endif
- while (1) {
- unsigned long real_start, real_size, aligned_size;
- aligned_size = real_size = host_size;
+ /*
+ * Expand the allocation to the entire reserved_va.
+ * Exclude the mmap_min_addr hole.
+ */
+ if (reserved_va) {
+ guest_loaddr = (guest_base >= mmap_min_addr ? 0
+ : mmap_min_addr - guest_base);
+ guest_hiaddr = reserved_va;
+ }
- /* Do not use mmap_find_vma here because that is limited to the
- * guest address space. We are going to make the
- * guest address space fit whatever we're given.
- */
- real_start = (unsigned long)
- mmap((void *)current_start, host_size, PROT_NONE, flags, -1, 0);
- if (real_start == (unsigned long)-1) {
- return (unsigned long)-1;
- }
+ /* Reserve the address space for the binary, or reserved_va. */
+ test = g2h(guest_loaddr);
+ addr = mmap(test, guest_hiaddr - guest_loaddr, PROT_NONE, flags, -1, 0);
+ if (test != addr) {
+ pgb_fail_in_use(image_name);
+ }
+}
- /* Check to see if the address is valid. */
- if (host_start && real_start != current_start) {
- qemu_log_mask(CPU_LOG_PAGE, "invalid %lx && %lx != %lx\n",
- host_start, real_start, current_start);
- goto try_again;
+/* Return value for guest_base, or -1 if no hole found. */
+static uintptr_t pgb_find_hole(uintptr_t guest_loaddr, uintptr_t guest_size,
+ long align)
+{
+ GSList *maps, *iter;
+ uintptr_t this_start, this_end, next_start, brk;
+ intptr_t ret = -1;
+
+ assert(QEMU_IS_ALIGNED(guest_loaddr, align));
+
+ maps = read_self_maps();
+
+ /* Read brk after we've read the maps, which will malloc. */
+ brk = (uintptr_t)sbrk(0);
+
+ /* The first hole is before the first map entry. */
+ this_start = mmap_min_addr;
+
+ for (iter = maps; iter;
+ this_start = next_start, iter = g_slist_next(iter)) {
+ uintptr_t align_start, hole_size;
+
+ this_end = ((MapInfo *)iter->data)->start;
+ next_start = ((MapInfo *)iter->data)->end;
+ align_start = ROUND_UP(this_start, align);
+
+ /* Skip holes that are too small. */
+ if (align_start >= this_end) {
+ continue;
+ }
+ hole_size = this_end - align_start;
+ if (hole_size < guest_size) {
+ continue;
}
- /* Ensure the address is properly aligned. */
- if (real_start & (align - 1)) {
- /* Ideally, we adjust like
- *
- * pages: [ ][ ][ ][ ][ ]
- * old: [ real ]
- * [ aligned ]
- * new: [ real ]
- * [ aligned ]
- *
- * But if there is something else mapped right after it,
- * then obviously it won't have room to grow, and the
- * kernel will put the new larger real someplace else with
- * unknown alignment (if we made it to here, then
- * fixed=false). Which is why we grow real by a full page
- * size, instead of by part of one; so that even if we get
- * moved, we can still guarantee alignment. But this does
- * mean that there is a padding of < 1 page both before
- * and after the aligned range; the "after" could could
- * cause problems for ARM emulation where it could butt in
- * to where we need to put the commpage.
- */
- munmap((void *)real_start, host_size);
- real_size = aligned_size + align;
- real_start = (unsigned long)
- mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0);
- if (real_start == (unsigned long)-1) {
- return (unsigned long)-1;
+ /* If this hole contains brk, give ourselves some room to grow. */
+ if (this_start <= brk && brk < this_end) {
+ hole_size -= guest_size;
+ if (sizeof(uintptr_t) == 8 && hole_size >= 1 * GiB) {
+ align_start += 1 * GiB;
+ } else if (hole_size >= 16 * MiB) {
+ align_start += 16 * MiB;
+ } else {
+ align_start = (this_end - guest_size) & -align;
+ if (align_start < this_start) {
+ continue;
+ }
}
- aligned_start = ROUND_UP(real_start, align);
- } else {
- aligned_start = real_start;
}
-#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
- /* On 32-bit ARM, we need to also be able to map the commpage. */
- int valid = init_guest_commpage(aligned_start - guest_start,
- aligned_size + guest_start);
- if (valid == -1) {
- munmap((void *)real_start, real_size);
- return (unsigned long)-1;
- } else if (valid == 0) {
- goto try_again;
+ /* Record the lowest successful match. */
+ if (ret < 0) {
+ ret = align_start - guest_loaddr;
}
-#endif
-
- /* If nothing has said `return -1` or `goto try_again` yet,
- * then the address we have is good.
- */
- break;
-
- try_again:
- /* That address didn't work. Unmap and try a different one.
- * The address the host picked because is typically right at
- * the top of the host address space and leaves the guest with
- * no usable address space. Resort to a linear search. We
- * already compensated for mmap_min_addr, so this should not
- * happen often. Probably means we got unlucky and host
- * address space randomization put a shared library somewhere
- * inconvenient.
- *
- * This is probably a good strategy if host_start, but is
- * probably a bad strategy if not, which means we got here
- * because of trouble with ARM commpage setup.
- */
- if (munmap((void *)real_start, real_size) != 0) {
- error_report("%s: failed to unmap %lx:%lx (%s)", __func__,
- real_start, real_size, strerror(errno));
- abort();
+ /* If this hole contains the identity map, select it. */
+ if (align_start <= guest_loaddr &&
+ guest_loaddr + guest_size <= this_end) {
+ ret = 0;
}
- current_start += align;
- if (host_start == current_start) {
- /* Theoretically possible if host doesn't have any suitably
- * aligned areas. Normally the first mmap will fail.
- */
- return (unsigned long)-1;
+ /* If this hole ends above the identity map, stop looking. */
+ if (this_end >= guest_loaddr) {
+ break;
}
}
+ free_self_maps(maps);
- qemu_log_mask(CPU_LOG_PAGE, "Reserved 0x%lx bytes of guest address space\n", host_size);
-
- return aligned_start;
+ return ret;
}
-static void probe_guest_base(const char *image_name,
- abi_ulong loaddr, abi_ulong hiaddr)
+static void pgb_static(const char *image_name, abi_ulong orig_loaddr,
+ abi_ulong orig_hiaddr, long align)
{
- /* Probe for a suitable guest base address, if the user has not set
- * it explicitly, and set guest_base appropriately.
- * In case of error we will print a suitable message and exit.
- */
- const char *errmsg;
- if (!have_guest_base && !reserved_va) {
- unsigned long host_start, real_start, host_size;
+ uintptr_t loaddr = orig_loaddr;
+ uintptr_t hiaddr = orig_hiaddr;
+ uintptr_t addr;
- /* Round addresses to page boundaries. */
- loaddr &= qemu_host_page_mask;
- hiaddr = HOST_PAGE_ALIGN(hiaddr);
+ if (hiaddr != orig_hiaddr) {
+ error_report("%s: requires virtual address space that the "
+ "host cannot provide (0x%" PRIx64 ")",
+ image_name, (uint64_t)orig_hiaddr);
+ exit(EXIT_FAILURE);
+ }
- if (loaddr < mmap_min_addr) {
- host_start = HOST_PAGE_ALIGN(mmap_min_addr);
+ loaddr &= -align;
+ if (ARM_COMMPAGE) {
+ /*
+ * Extend the allocation to include the commpage.
+ * For a 64-bit host, this is just 4GiB; for a 32-bit host,
+ * the address arithmetic will wrap around, but the difference
+ * will produce the correct allocation size.
+ */
+ if (sizeof(uintptr_t) == 8 || loaddr >= 0x80000000u) {
+ hiaddr = (uintptr_t)4 << 30;
} else {
- host_start = loaddr;
- if (host_start != loaddr) {
- errmsg = "Address overflow loading ELF binary";
- goto exit_errmsg;
- }
+ loaddr = ARM_COMMPAGE & -align;
}
- host_size = hiaddr - loaddr;
+ }
- /* Setup the initial guest memory space with ranges gleaned from
- * the ELF image that is being loaded.
+ addr = pgb_find_hole(loaddr, hiaddr - loaddr, align);
+ if (addr == -1) {
+ /*
+ * If ARM_COMMPAGE, there *might* be a non-consecutive allocation
+ * that can satisfy both. But as the normal arm32 link base address
+ * is ~32k, and we extend down to include the commpage, making the
+ * overhead only ~96k, this is unlikely.
*/
- real_start = init_guest_space(host_start, host_size, loaddr, false);
- if (real_start == (unsigned long)-1) {
- errmsg = "Unable to find space for application";
- goto exit_errmsg;
- }
- guest_base = real_start - loaddr;
+ error_report("%s: Unable to allocate %#zx bytes of "
+ "virtual address space", image_name,
+ (size_t)(hiaddr - loaddr));
+ exit(EXIT_FAILURE);
+ }
+
+ guest_base = addr;
+}
+
+static void pgb_dynamic(const char *image_name, long align)
+{
+ /*
+ * The executable is dynamic and does not require a fixed address.
+ * All we need is a commpage that satisfies align.
+ * If we do not need a commpage, leave guest_base == 0.
+ */
+ if (ARM_COMMPAGE) {
+ uintptr_t addr, commpage;
- qemu_log_mask(CPU_LOG_PAGE, "Relocating guest address space from 0x"
- TARGET_ABI_FMT_lx " to 0x%lx\n",
- loaddr, real_start);
+ /* 64-bit hosts should have used reserved_va. */
+ assert(sizeof(uintptr_t) == 4);
+
+ /*
+ * By putting the commpage at the first hole, that puts guest_base
+ * just above that, and maximises the positive guest addresses.
+ */
+ commpage = ARM_COMMPAGE & -align;
+ addr = pgb_find_hole(commpage, -commpage, align);
+ assert(addr != -1);
+ guest_base = addr;
}
- return;
+}
-exit_errmsg:
- fprintf(stderr, "%s: %s\n", image_name, errmsg);
- exit(-1);
+static void pgb_reserved_va(const char *image_name, abi_ulong guest_loaddr,
+ abi_ulong guest_hiaddr, long align)
+{
+ const int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
+ void *addr, *test;
+
+ if (guest_hiaddr > reserved_va) {
+ error_report("%s: requires more than reserved virtual "
+ "address space (0x%" PRIx64 " > 0x%lx)",
+ image_name, (uint64_t)guest_hiaddr, reserved_va);
+ exit(EXIT_FAILURE);
+ }
+
+ /* Widen the "image" to the entire reserved address space. */
+ pgb_static(image_name, 0, reserved_va, align);
+
+ /* Reserve the memory on the host. */
+ assert(guest_base != 0);
+ test = g2h(0);
+ addr = mmap(test, reserved_va, PROT_NONE, flags, -1, 0);
+ if (addr == MAP_FAILED) {
+ error_report("Unable to reserve 0x%lx bytes of virtual address "
+ "space for use as guest address space (check your "
+ "virtual memory ulimit setting or reserve less "
+ "using -R option)", reserved_va);
+ exit(EXIT_FAILURE);
+ }
+ assert(addr == test);
}
+void probe_guest_base(const char *image_name, abi_ulong guest_loaddr,
+ abi_ulong guest_hiaddr)
+{
+ /* In order to use host shmat, we must be able to honor SHMLBA. */
+ uintptr_t align = MAX(SHMLBA, qemu_host_page_size);
+
+ if (have_guest_base) {
+ pgb_have_guest_base(image_name, guest_loaddr, guest_hiaddr, align);
+ } else if (reserved_va) {
+ pgb_reserved_va(image_name, guest_loaddr, guest_hiaddr, align);
+ } else if (guest_loaddr) {
+ pgb_static(image_name, guest_loaddr, guest_hiaddr, align);
+ } else {
+ pgb_dynamic(image_name, align);
+ }
+
+ /* Reserve and initialize the commpage. */
+ if (!init_guest_commpage()) {
+ /*
+ * With have_guest_base, the user has selected the address and
+ * we are trying to work with that. Otherwise, we have selected
+ * free space and init_guest_commpage must succeeded.
+ */
+ assert(have_guest_base);
+ pgb_fail_in_use(image_name);
+ }
+
+ assert(QEMU_IS_ALIGNED(guest_base, align));
+ qemu_log_mask(CPU_LOG_PAGE, "Locating guest address space "
+ "@ 0x%" PRIx64 "\n", (uint64_t)guest_base);
+}
/* Load an ELF image into the address space.
@@ -2399,6 +2390,12 @@ static void load_elf_image(const char *image_name, int image_fd,
* MMAP_MIN_ADDR or the QEMU application itself.
*/
probe_guest_base(image_name, loaddr, hiaddr);
+ } else {
+ /*
+ * The binary is dynamic, but we still need to
+ * select guest_base. In this case we pass a size.
+ */
+ probe_guest_base(image_name, 0, hiaddr - loaddr);
}
}
diff --git a/linux-user/flatload.c b/linux-user/flatload.c
index 66901f39cc5..8fb448f0bf0 100644
--- a/linux-user/flatload.c
+++ b/linux-user/flatload.c
@@ -441,6 +441,12 @@ static int load_flat_file(struct linux_binprm * bprm,
indx_len = MAX_SHARED_LIBS * sizeof(abi_ulong);
indx_len = (indx_len + 15) & ~(abi_ulong)15;
+ /*
+ * Alloate the address space.
+ */
+ probe_guest_base(bprm->filename, 0,
+ text_len + data_len + extra + indx_len);
+
/*
* there are a couple of cases here, the separate code/data
* case, and then the fully copied to RAM case which lumps
diff --git a/linux-user/main.c b/linux-user/main.c
index 2cd443237d8..e18c1fb9523 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -24,6 +24,7 @@
#include "qemu-version.h"
#include <sys/syscall.h>
#include <sys/resource.h>
+#include <sys/shm.h>
#include "qapi/error.h"
#include "qemu.h"
@@ -747,28 +748,6 @@ int main(int argc, char **argv, char **envp)
target_environ = envlist_to_environ(envlist, NULL);
envlist_free(envlist);
- /*
- * Now that page sizes are configured in tcg_exec_init() we can do
- * proper page alignment for guest_base.
- */
- guest_base = HOST_PAGE_ALIGN(guest_base);
-
- if (reserved_va || have_guest_base) {
- guest_base = init_guest_space(guest_base, reserved_va, 0,
- have_guest_base);
- if (guest_base == (unsigned long)-1) {
- fprintf(stderr, "Unable to reserve 0x%lx bytes of virtual address "
- "space for use as guest address space (check your virtual "
- "memory ulimit setting or reserve less using -R option)\n",
- reserved_va);
- exit(EXIT_FAILURE);
- }
-
- if (reserved_va) {
- mmap_next_start = reserved_va;
- }
- }
-
/*
* Read in mmap_min_addr kernel parameter. This value is used
* When loading the ELF image to determine whether guest_base
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* Re: [PATCH v1 04/10] linux-user: completely re-write init_guest_space
2020-05-13 17:51 ` [PATCH v1 04/10] linux-user: completely re-write init_guest_space Alex Bennée
@ 2020-05-21 4:43 ` Thomas Huth
2020-05-21 8:21 ` Alex Bennée
0 siblings, 1 reply; 19+ messages in thread
From: Thomas Huth @ 2020-05-21 4:43 UTC (permalink / raw)
To: Alex Bennée, qemu-devel; +Cc: Riku Voipio, Laurent Vivier, Cornelia Huck
On 13/05/2020 19.51, Alex Bennée wrote:
> First we ensure all guest space initialisation logic comes through
> probe_guest_base once we understand the nature of the binary we are
> loading. The convoluted init_guest_space routine is removed and
> replaced with a number of pgb_* helpers which are called depending on
> what requirements we have when loading the binary.
>
> We first try to do what is requested by the host. Failing that we try
> and satisfy the guest requested base address. If all those options
> fail we fall back to finding a space in the memory map using our
> recently written read_self_maps() helper.
>
> There are some additional complications we try and take into account
> when looking for holes in the address space. We try not to go directly
> after the system brk() space so there is space for a little growth. We
> also don't want to have to use negative offsets which would result in
> slightly less efficient code on x86 when it's unable to use the
> segment offset register.
>
> Less mind-binding gotos and hopefully clearer logic throughout.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Acked-by: Laurent Vivier <laurent@vivier.eu>
[...]
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 619c054cc48..01a9323a637 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -11,6 +11,7 @@
> #include "qemu/queue.h"
> #include "qemu/guest-random.h"
> #include "qemu/units.h"
> +#include "qemu/selfmap.h"
>
> #ifdef _ARCH_PPC64
> #undef ARCH_DLINFO
> @@ -382,68 +383,30 @@ enum {
>
> /* The commpage only exists for 32 bit kernels */
>
> -/* Return 1 if the proposed guest space is suitable for the guest.
> - * Return 0 if the proposed guest space isn't suitable, but another
> - * address space should be tried.
> - * Return -1 if there is no way the proposed guest space can be
> - * valid regardless of the base.
> - * The guest code may leave a page mapped and populate it if the
> - * address is suitable.
> - */
> -static int init_guest_commpage(unsigned long guest_base,
> - unsigned long guest_size)
> -{
> - unsigned long real_start, test_page_addr;
> -
> - /* We need to check that we can force a fault on access to the
> - * commpage at 0xffff0fxx
> - */
> - test_page_addr = guest_base + (0xffff0f00 & qemu_host_page_mask);
> -
> - /* If the commpage lies within the already allocated guest space,
> - * then there is no way we can allocate it.
> - *
> - * You may be thinking that that this check is redundant because
> - * we already validated the guest size against MAX_RESERVED_VA;
> - * but if qemu_host_page_mask is unusually large, then
> - * test_page_addr may be lower.
> - */
> - if (test_page_addr >= guest_base
> - && test_page_addr < (guest_base + guest_size)) {
> - return -1;
> - }
> +#define ARM_COMMPAGE (intptr_t)0xffff0f00u
>
> - /* Note it needs to be writeable to let us initialise it */
> - real_start = (unsigned long)
> - mmap((void *)test_page_addr, qemu_host_page_size,
> - PROT_READ | PROT_WRITE,
> - MAP_ANONYMOUS | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> +static bool init_guest_commpage(void)
> +{
> + void *want = g2h(ARM_COMMPAGE & -qemu_host_page_size);
> + void *addr = mmap(want, qemu_host_page_size, PROT_READ | PROT_WRITE,
> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
>
> - /* If we can't map it then try another address */
> - if (real_start == -1ul) {
> - return 0;
> + if (addr == MAP_FAILED) {
> + perror("Allocating guest commpage");
> + exit(EXIT_FAILURE);
> }
> -
> - if (real_start != test_page_addr) {
> - /* OS didn't put the page where we asked - unmap and reject */
> - munmap((void *)real_start, qemu_host_page_size);
> - return 0;
> + if (addr != want) {
> + return false;
> }
>
> - /* Leave the page mapped
> - * Populate it (mmap should have left it all 0'd)
> - */
> -
> - /* Kernel helper versions */
> - __put_user(5, (uint32_t *)g2h(0xffff0ffcul));
> + /* Set kernel helper versions; rest of page is 0. */
> + __put_user(5, (uint32_t *)g2h(0xffff0ffcu));
>
> - /* Now it's populated make it RO */
> - if (mprotect((void *)test_page_addr, qemu_host_page_size, PROT_READ)) {
> + if (mprotect(addr, qemu_host_page_size, PROT_READ)) {
> perror("Protecting guest commpage");
> - exit(-1);
> + exit(EXIT_FAILURE);
> }
> -
> - return 1; /* All good */
> + return true;
> }
>
> #define ELF_HWCAP get_elf_hwcap()
> @@ -2075,239 +2038,267 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
> return sp;
> }
>
> -unsigned long init_guest_space(unsigned long host_start,
> - unsigned long host_size,
> - unsigned long guest_start,
> - bool fixed)
> -{
> - /* In order to use host shmat, we must be able to honor SHMLBA. */
> - unsigned long align = MAX(SHMLBA, qemu_host_page_size);
> - unsigned long current_start, aligned_start;
> - int flags;
> -
> - assert(host_start || host_size);
> -
> - /* If just a starting address is given, then just verify that
> - * address. */
> - if (host_start && !host_size) {
> -#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
> - if (init_guest_commpage(host_start, host_size) != 1) {
> - return (unsigned long)-1;
> - }
> +#ifndef ARM_COMMPAGE
> +#define ARM_COMMPAGE 0
> +#define init_guest_commpage() true
> #endif
> - return host_start;
> - }
>
> - /* Setup the initial flags and start address. */
> - current_start = host_start & -align;
> - flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
> - if (fixed) {
> - flags |= MAP_FIXED;
> - }
> +static void pgb_fail_in_use(const char *image_name)
> +{
> + error_report("%s: requires virtual address space that is in use "
> + "(omit the -B option or choose a different value)",
> + image_name);
> + exit(EXIT_FAILURE);
> +}
>
> - /* Otherwise, a non-zero size region of memory needs to be mapped
> - * and validated. */
> +static void pgb_have_guest_base(const char *image_name, abi_ulong guest_loaddr,
> + abi_ulong guest_hiaddr, long align)
> +{
> + const int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE;
> + void *addr, *test;
>
> -#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
> - /* On 32-bit ARM, we need to map not just the usable memory, but
> - * also the commpage. Try to find a suitable place by allocating
> - * a big chunk for all of it. If host_start, then the naive
> - * strategy probably does good enough.
> - */
> - if (!host_start) {
> - unsigned long guest_full_size, host_full_size, real_start;
> -
> - guest_full_size =
> - (0xffff0f00 & qemu_host_page_mask) + qemu_host_page_size;
> - host_full_size = guest_full_size - guest_start;
> - real_start = (unsigned long)
> - mmap(NULL, host_full_size, PROT_NONE, flags, -1, 0);
> - if (real_start == (unsigned long)-1) {
> - if (host_size < host_full_size - qemu_host_page_size) {
> - /* We failed to map a continous segment, but we're
> - * allowed to have a gap between the usable memory and
> - * the commpage where other things can be mapped.
> - * This sparseness gives us more flexibility to find
> - * an address range.
> - */
> - goto naive;
> - }
> - return (unsigned long)-1;
> + if (!QEMU_IS_ALIGNED(guest_base, align)) {
> + fprintf(stderr, "Requested guest base 0x%lx does not satisfy "
> + "host minimum alignment (0x%lx)\n",
> + guest_base, align);
> + exit(EXIT_FAILURE);
> + }
> +
> + /* Sanity check the guest binary. */
> + if (reserved_va) {
> + if (guest_hiaddr > reserved_va) {
> + error_report("%s: requires more than reserved virtual "
> + "address space (0x%" PRIx64 " > 0x%lx)",
> + image_name, (uint64_t)guest_hiaddr, reserved_va);
> + exit(EXIT_FAILURE);
> }
> - munmap((void *)real_start, host_full_size);
> - if (real_start & (align - 1)) {
> - /* The same thing again, but with extra
> - * so that we can shift around alignment.
> - */
> - unsigned long real_size = host_full_size + qemu_host_page_size;
> - real_start = (unsigned long)
> - mmap(NULL, real_size, PROT_NONE, flags, -1, 0);
> - if (real_start == (unsigned long)-1) {
> - if (host_size < host_full_size - qemu_host_page_size) {
> - goto naive;
> - }
> - return (unsigned long)-1;
> - }
> - munmap((void *)real_start, real_size);
> - real_start = ROUND_UP(real_start, align);
> + } else {
> + if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
> + error_report("%s: requires more virtual address space "
> + "than the host can provide (0x%" PRIx64 ")",
> + image_name, (uint64_t)guest_hiaddr - guest_base);
> + exit(EXIT_FAILURE);
> }
Hi Alex,
this causes an error with newer versions of Clang:
linux-user/elfload.c:2076:41: error: result of comparison 'unsigned
long' > 18446744073709551615 is always false
[-Werror,-Wtautological-type-limit-compare]
4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
4687 1 error generated.
Any ideas how to fix this?
Thomas
^ permalink raw reply [flat|nested] 19+ messages in thread* Re: [PATCH v1 04/10] linux-user: completely re-write init_guest_space
2020-05-21 4:43 ` Thomas Huth
@ 2020-05-21 8:21 ` Alex Bennée
2020-05-21 15:39 ` Richard Henderson
0 siblings, 1 reply; 19+ messages in thread
From: Alex Bennée @ 2020-05-21 8:21 UTC (permalink / raw)
To: Thomas Huth; +Cc: Cornelia Huck, Riku Voipio, qemu-devel, Laurent Vivier
Thomas Huth <thuth@redhat.com> writes:
> On 13/05/2020 19.51, Alex Bennée wrote:
>> First we ensure all guest space initialisation logic comes through
>> probe_guest_base once we understand the nature of the binary we are
>> loading. The convoluted init_guest_space routine is removed and
>> replaced with a number of pgb_* helpers which are called depending on
>> what requirements we have when loading the binary.
>>
>> We first try to do what is requested by the host. Failing that we try
>> and satisfy the guest requested base address. If all those options
>> fail we fall back to finding a space in the memory map using our
>> recently written read_self_maps() helper.
>>
>> There are some additional complications we try and take into account
>> when looking for holes in the address space. We try not to go directly
>> after the system brk() space so there is space for a little growth. We
>> also don't want to have to use negative offsets which would result in
>> slightly less efficient code on x86 when it's unable to use the
>> segment offset register.
>>
>> Less mind-binding gotos and hopefully clearer logic throughout.
>>
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> Acked-by: Laurent Vivier <laurent@vivier.eu>
<snip>
>> + } else {
>> + if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
>> + error_report("%s: requires more virtual address space "
>> + "than the host can provide (0x%" PRIx64 ")",
>> + image_name, (uint64_t)guest_hiaddr - guest_base);
>> + exit(EXIT_FAILURE);
>> }
>
> Hi Alex,
>
> this causes an error with newer versions of Clang:
>
> linux-user/elfload.c:2076:41: error: result of comparison 'unsigned
> long' > 18446744073709551615 is always false
> [-Werror,-Wtautological-type-limit-compare]
> 4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
> 4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
> 4687 1 error generated.
>
> Any ideas how to fix this?
I guess this check only makes sense when abi_ulong > uintptr_t or IOW 64
bit guests running on 32 bit hosts. We could just wrap that check in:
#if HOST_LONG_BITS == 32
#endif
>
> Thomas
--
Alex Bennée
^ permalink raw reply [flat|nested] 19+ messages in thread* Re: [PATCH v1 04/10] linux-user: completely re-write init_guest_space
2020-05-21 8:21 ` Alex Bennée
@ 2020-05-21 15:39 ` Richard Henderson
2020-05-22 10:24 ` Alex Bennée
0 siblings, 1 reply; 19+ messages in thread
From: Richard Henderson @ 2020-05-21 15:39 UTC (permalink / raw)
To: Alex Bennée, Thomas Huth
Cc: Riku Voipio, Cornelia Huck, qemu-devel, Laurent Vivier
On 5/21/20 1:21 AM, Alex Bennée wrote:
>
> Thomas Huth <thuth@redhat.com> writes:
>
>> On 13/05/2020 19.51, Alex Bennée wrote:
>>> First we ensure all guest space initialisation logic comes through
>>> probe_guest_base once we understand the nature of the binary we are
>>> loading. The convoluted init_guest_space routine is removed and
>>> replaced with a number of pgb_* helpers which are called depending on
>>> what requirements we have when loading the binary.
>>>
>>> We first try to do what is requested by the host. Failing that we try
>>> and satisfy the guest requested base address. If all those options
>>> fail we fall back to finding a space in the memory map using our
>>> recently written read_self_maps() helper.
>>>
>>> There are some additional complications we try and take into account
>>> when looking for holes in the address space. We try not to go directly
>>> after the system brk() space so there is space for a little growth. We
>>> also don't want to have to use negative offsets which would result in
>>> slightly less efficient code on x86 when it's unable to use the
>>> segment offset register.
>>>
>>> Less mind-binding gotos and hopefully clearer logic throughout.
>>>
>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>> Acked-by: Laurent Vivier <laurent@vivier.eu>
> <snip>
>>> + } else {
>>> + if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
>>> + error_report("%s: requires more virtual address space "
>>> + "than the host can provide (0x%" PRIx64 ")",
>>> + image_name, (uint64_t)guest_hiaddr - guest_base);
>>> + exit(EXIT_FAILURE);
>>> }
>>
>> Hi Alex,
>>
>> this causes an error with newer versions of Clang:
>>
>> linux-user/elfload.c:2076:41: error: result of comparison 'unsigned
>> long' > 18446744073709551615 is always false
>> [-Werror,-Wtautological-type-limit-compare]
>> 4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
>> 4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
>> 4687 1 error generated.
>>
>> Any ideas how to fix this?
>
> I guess this check only makes sense when abi_ulong > uintptr_t or IOW 64
> bit guests running on 32 bit hosts. We could just wrap that check in:
>
> #if HOST_LONG_BITS == 32
>
> #endif
As I've suggested elsewhere, I think we should disable this warning on the
command-line.
r~
^ permalink raw reply [flat|nested] 19+ messages in thread* Re: [PATCH v1 04/10] linux-user: completely re-write init_guest_space
2020-05-21 15:39 ` Richard Henderson
@ 2020-05-22 10:24 ` Alex Bennée
2020-05-22 10:36 ` Peter Maydell
0 siblings, 1 reply; 19+ messages in thread
From: Alex Bennée @ 2020-05-22 10:24 UTC (permalink / raw)
To: Richard Henderson
Cc: Thomas Huth, Cornelia Huck, Riku Voipio, qemu-devel, Laurent Vivier
Richard Henderson <richard.henderson@linaro.org> writes:
> On 5/21/20 1:21 AM, Alex Bennée wrote:
>>
>> Thomas Huth <thuth@redhat.com> writes:
>>
>>> On 13/05/2020 19.51, Alex Bennée wrote:
>>>> First we ensure all guest space initialisation logic comes through
>>>> probe_guest_base once we understand the nature of the binary we are
>>>> loading. The convoluted init_guest_space routine is removed and
>>>> replaced with a number of pgb_* helpers which are called depending on
>>>> what requirements we have when loading the binary.
>>>>
>>>> We first try to do what is requested by the host. Failing that we try
>>>> and satisfy the guest requested base address. If all those options
>>>> fail we fall back to finding a space in the memory map using our
>>>> recently written read_self_maps() helper.
>>>>
>>>> There are some additional complications we try and take into account
>>>> when looking for holes in the address space. We try not to go directly
>>>> after the system brk() space so there is space for a little growth. We
>>>> also don't want to have to use negative offsets which would result in
>>>> slightly less efficient code on x86 when it's unable to use the
>>>> segment offset register.
>>>>
>>>> Less mind-binding gotos and hopefully clearer logic throughout.
>>>>
>>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>>> Acked-by: Laurent Vivier <laurent@vivier.eu>
>> <snip>
>>>> + } else {
>>>> + if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
>>>> + error_report("%s: requires more virtual address space "
>>>> + "than the host can provide (0x%" PRIx64 ")",
>>>> + image_name, (uint64_t)guest_hiaddr - guest_base);
>>>> + exit(EXIT_FAILURE);
>>>> }
>>>
>>> Hi Alex,
>>>
>>> this causes an error with newer versions of Clang:
>>>
>>> linux-user/elfload.c:2076:41: error: result of comparison 'unsigned
>>> long' > 18446744073709551615 is always false
>>> [-Werror,-Wtautological-type-limit-compare]
>>> 4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
>>> 4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
>>> 4687 1 error generated.
>>>
>>> Any ideas how to fix this?
>>
>> I guess this check only makes sense when abi_ulong > uintptr_t or IOW 64
>> bit guests running on 32 bit hosts. We could just wrap that check in:
>>
>> #if HOST_LONG_BITS == 32
>>
>> #endif
>
> As I've suggested elsewhere, I think we should disable this warning on the
> command-line.
Yeah - although after having pushed down this bug it seems there are
still a lot of things clang-10 is finding. I think maybe I should punt
the fedora32 bump to a new series of clang-10 fixups?
Examples:
/tmp/qemu-test/src/fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/audio/mixeng.c:274:34: error: implicit conversion from 'unsigned int' to 'float' changes value from 4294967295 to 4294967296 [-Werror,-Wimplicit-int-float-conversion]
static const float float_scale = UINT_MAX / 2.f;
^~~~~~~~ ~
/usr/lib64/clang/10.0.0/include/limits.h:56:37: note: expanded from macro 'UINT_MAX'
#define UINT_MAX (__INT_MAX__ *2U +1U)
~~~~~~~~~~~~~~~~~^~~
--
Alex Bennée
^ permalink raw reply [flat|nested] 19+ messages in thread* Re: [PATCH v1 04/10] linux-user: completely re-write init_guest_space
2020-05-22 10:24 ` Alex Bennée
@ 2020-05-22 10:36 ` Peter Maydell
0 siblings, 0 replies; 19+ messages in thread
From: Peter Maydell @ 2020-05-22 10:36 UTC (permalink / raw)
To: Alex Bennée
Cc: Thomas Huth, Riku Voipio, Cornelia Huck, Richard Henderson,
QEMU Developers, Laurent Vivier
On Fri, 22 May 2020 at 11:24, Alex Bennée <alex.bennee@linaro.org> wrote:
> Examples:
>
> /tmp/qemu-test/src/fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
> absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> !
> /tmp/qemu-test/src/fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
> absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> !
These warnings as printed seem like compiler bugs -- '&' is a bitwise
operator, not a boolean one. (Probably the compiler intends to warn
about use of the bitwise & on the boolean == result, though.)
thanks
-- PMM
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH v1 05/10] exec/cpu-all: Use bool for have_guest_base
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
` (3 preceding siblings ...)
2020-05-13 17:51 ` [PATCH v1 04/10] linux-user: completely re-write init_guest_space Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-13 18:18 ` Laurent Vivier
2020-05-13 17:51 ` [PATCH v1 06/10] accel/tcg: Relax va restrictions on 64-bit guests Alex Bennée
` (4 subsequent siblings)
9 siblings, 1 reply; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel
Cc: Philippe Mathieu-Daudé,
Riku Voipio, Richard Henderson, Laurent Vivier, Paolo Bonzini,
Alex Bennée, Richard Henderson
From: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
include/exec/cpu-all.h | 2 +-
bsd-user/main.c | 4 ++--
linux-user/main.c | 4 ++--
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 43ddcf024c6..0895a57881a 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -159,7 +159,7 @@ static inline void tswap64s(uint64_t *s)
* This allows the guest address space to be offset to a convenient location.
*/
extern unsigned long guest_base;
-extern int have_guest_base;
+extern bool have_guest_base;
extern unsigned long reserved_va;
#if HOST_LONG_BITS <= TARGET_VIRT_ADDR_SPACE_BITS
diff --git a/bsd-user/main.c b/bsd-user/main.c
index 28f122b80e6..0bfe46cff93 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -42,7 +42,7 @@
int singlestep;
unsigned long mmap_min_addr;
unsigned long guest_base;
-int have_guest_base;
+bool have_guest_base;
unsigned long reserved_va;
static const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;
@@ -828,7 +828,7 @@ int main(int argc, char **argv)
}
} else if (!strcmp(r, "B")) {
guest_base = strtol(argv[optind++], NULL, 0);
- have_guest_base = 1;
+ have_guest_base = true;
} else if (!strcmp(r, "drop-ld-preload")) {
(void) envlist_unsetenv(envlist, "LD_PRELOAD");
} else if (!strcmp(r, "bsd")) {
diff --git a/linux-user/main.c b/linux-user/main.c
index e18c1fb9523..3597e99bb10 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -59,7 +59,7 @@ static const char *cpu_type;
static const char *seed_optarg;
unsigned long mmap_min_addr;
unsigned long guest_base;
-int have_guest_base;
+bool have_guest_base;
/*
* Used to implement backwards-compatibility for the `-strace`, and
@@ -334,7 +334,7 @@ static void handle_arg_cpu(const char *arg)
static void handle_arg_guest_base(const char *arg)
{
guest_base = strtol(arg, NULL, 0);
- have_guest_base = 1;
+ have_guest_base = true;
}
static void handle_arg_reserved_va(const char *arg)
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* Re: [PATCH v1 05/10] exec/cpu-all: Use bool for have_guest_base
2020-05-13 17:51 ` [PATCH v1 05/10] exec/cpu-all: Use bool for have_guest_base Alex Bennée
@ 2020-05-13 18:18 ` Laurent Vivier
0 siblings, 0 replies; 19+ messages in thread
From: Laurent Vivier @ 2020-05-13 18:18 UTC (permalink / raw)
To: Alex Bennée, qemu-devel
Cc: Philippe Mathieu-Daudé,
Riku Voipio, Paolo Bonzini, Richard Henderson, Richard Henderson
Le 13/05/2020 à 19:51, Alex Bennée a écrit :
> From: Richard Henderson <richard.henderson@linaro.org>
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
> include/exec/cpu-all.h | 2 +-
> bsd-user/main.c | 4 ++--
> linux-user/main.c | 4 ++--
> 3 files changed, 5 insertions(+), 5 deletions(-)
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH v1 06/10] accel/tcg: Relax va restrictions on 64-bit guests
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
` (4 preceding siblings ...)
2020-05-13 17:51 ` [PATCH v1 05/10] exec/cpu-all: Use bool for have_guest_base Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-13 17:51 ` [PATCH v1 07/10] accel/tcg: don't disable exec_tb trace events Alex Bennée
` (3 subsequent siblings)
9 siblings, 0 replies; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel
Cc: Alex Bennée, Paolo Bonzini, Richard Henderson, Richard Henderson
From: Richard Henderson <richard.henderson@linaro.org>
We cannot at present limit a 64-bit guest to a virtual address
space smaller than the host. It will mostly work to ignore this
limitation, except if the guest uses high bits of the address
space for tags. But it will certainly work better, as presently
we can wind up failing to allocate the guest stack.
Widen our user-only page tree to the host or abi pointer width.
Remove the workaround for this problem from target/alpha.
Always validate guest addresses vs reserved_va, as there we
control allocation ourselves.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
vN
- shutup checkpatch on ~0ul
---
include/exec/cpu-all.h | 23 +++++++++++++++++++----
target/alpha/cpu-param.h | 15 ++-------------
accel/tcg/translate-all.c | 15 +++++++++------
3 files changed, 30 insertions(+), 23 deletions(-)
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 0895a57881a..d14374bdd49 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -162,12 +162,27 @@ extern unsigned long guest_base;
extern bool have_guest_base;
extern unsigned long reserved_va;
-#if HOST_LONG_BITS <= TARGET_VIRT_ADDR_SPACE_BITS
-#define GUEST_ADDR_MAX (~0ul)
+/*
+ * Limit the guest addresses as best we can.
+ *
+ * When not using -R reserved_va, we cannot really limit the guest
+ * to less address space than the host. For 32-bit guests, this
+ * acts as a sanity check that we're not giving the guest an address
+ * that it cannot even represent. For 64-bit guests... the address
+ * might not be what the real kernel would give, but it is at least
+ * representable in the guest.
+ *
+ * TODO: Improve address allocation to avoid this problem, and to
+ * avoid setting bits at the top of guest addresses that might need
+ * to be used for tags.
+ */
+#if MIN(TARGET_VIRT_ADDR_SPACE_BITS, TARGET_ABI_BITS) <= 32
+# define GUEST_ADDR_MAX_ UINT32_MAX
#else
-#define GUEST_ADDR_MAX (reserved_va ? reserved_va - 1 : \
- (1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
+# define GUEST_ADDR_MAX_ (~0ul)
#endif
+#define GUEST_ADDR_MAX (reserved_va ? reserved_va - 1 : GUEST_ADDR_MAX_)
+
#else
#include "exec/hwaddr.h"
diff --git a/target/alpha/cpu-param.h b/target/alpha/cpu-param.h
index 692aee27ca9..1153992e42a 100644
--- a/target/alpha/cpu-param.h
+++ b/target/alpha/cpu-param.h
@@ -10,22 +10,11 @@
#define TARGET_LONG_BITS 64
#define TARGET_PAGE_BITS 13
-#ifdef CONFIG_USER_ONLY
-/*
- * ??? The kernel likes to give addresses in high memory. If the host has
- * more virtual address space than the guest, this can lead to impossible
- * allocations. Honor the long-standing assumption that only kernel addrs
- * are negative, but otherwise allow allocations anywhere. This could lead
- * to tricky emulation problems for programs doing tagged addressing, but
- * that's far fewer than encounter the impossible allocation problem.
- */
-#define TARGET_PHYS_ADDR_SPACE_BITS 63
-#define TARGET_VIRT_ADDR_SPACE_BITS 63
-#else
+
/* ??? EV4 has 34 phys addr bits, EV5 has 40, EV6 has 44. */
#define TARGET_PHYS_ADDR_SPACE_BITS 44
#define TARGET_VIRT_ADDR_SPACE_BITS (30 + TARGET_PAGE_BITS)
-#endif
+
#define NB_MMU_MODES 3
#endif
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 9924e66d1f7..e4f703a7e6d 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -173,8 +173,13 @@ struct page_collection {
#define TB_FOR_EACH_JMP(head_tb, tb, n) \
TB_FOR_EACH_TAGGED((head_tb)->jmp_list_head, tb, n, jmp_list_next)
-/* In system mode we want L1_MAP to be based on ram offsets,
- while in user mode we want it to be based on virtual addresses. */
+/*
+ * In system mode we want L1_MAP to be based on ram offsets,
+ * while in user mode we want it to be based on virtual addresses.
+ *
+ * TODO: For user mode, see the caveat re host vs guest virtual
+ * address spaces near GUEST_ADDR_MAX.
+ */
#if !defined(CONFIG_USER_ONLY)
#if HOST_LONG_BITS < TARGET_PHYS_ADDR_SPACE_BITS
# define L1_MAP_ADDR_SPACE_BITS HOST_LONG_BITS
@@ -182,7 +187,7 @@ struct page_collection {
# define L1_MAP_ADDR_SPACE_BITS TARGET_PHYS_ADDR_SPACE_BITS
#endif
#else
-# define L1_MAP_ADDR_SPACE_BITS TARGET_VIRT_ADDR_SPACE_BITS
+# define L1_MAP_ADDR_SPACE_BITS MIN(HOST_LONG_BITS, TARGET_ABI_BITS)
#endif
/* Size of the L2 (and L3, etc) page tables. */
@@ -2497,9 +2502,7 @@ void page_set_flags(target_ulong start, target_ulong end, int flags)
/* This function should never be called with addresses outside the
guest address space. If this assert fires, it probably indicates
a missing call to h2g_valid. */
-#if TARGET_ABI_BITS > L1_MAP_ADDR_SPACE_BITS
- assert(end <= ((target_ulong)1 << L1_MAP_ADDR_SPACE_BITS));
-#endif
+ assert(end - 1 <= GUEST_ADDR_MAX);
assert(start < end);
assert_memory_lock();
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* [PATCH v1 07/10] accel/tcg: don't disable exec_tb trace events
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
` (5 preceding siblings ...)
2020-05-13 17:51 ` [PATCH v1 06/10] accel/tcg: Relax va restrictions on 64-bit guests Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-13 17:51 ` [PATCH v1 08/10] disas: include an optional note for the start of disassembly Alex Bennée
` (2 subsequent siblings)
9 siblings, 0 replies; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel
Cc: Philippe Mathieu-Daudé,
Paolo Bonzini, Alex Bennée, Richard Henderson
I doubt the well predicted trace event check is particularly special in
the grand context of TCG code execution.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
accel/tcg/trace-events | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/accel/tcg/trace-events b/accel/tcg/trace-events
index 01852217a66..385b9f749b8 100644
--- a/accel/tcg/trace-events
+++ b/accel/tcg/trace-events
@@ -1,10 +1,10 @@
# See docs/devel/tracing.txt for syntax documentation.
-# TCG related tracing (mostly disabled by default)
+# TCG related tracing
# cpu-exec.c
-disable exec_tb(void *tb, uintptr_t pc) "tb:%p pc=0x%"PRIxPTR
-disable exec_tb_nocache(void *tb, uintptr_t pc) "tb:%p pc=0x%"PRIxPTR
-disable exec_tb_exit(void *last_tb, unsigned int flags) "tb:%p flags=0x%x"
+exec_tb(void *tb, uintptr_t pc) "tb:%p pc=0x%"PRIxPTR
+exec_tb_nocache(void *tb, uintptr_t pc) "tb:%p pc=0x%"PRIxPTR
+exec_tb_exit(void *last_tb, unsigned int flags) "tb:%p flags=0x%x"
# translate-all.c
translate_block(void *tb, uintptr_t pc, uint8_t *tb_code) "tb:%p, pc:0x%"PRIxPTR", tb_code:%p"
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* [PATCH v1 08/10] disas: include an optional note for the start of disassembly
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
` (6 preceding siblings ...)
2020-05-13 17:51 ` [PATCH v1 07/10] accel/tcg: don't disable exec_tb trace events Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-13 17:51 ` [PATCH v1 09/10] disas: add optional note support to cap_disas Alex Bennée
2020-05-13 17:51 ` [PATCH v1 10/10] translate-all: include guest address in out_asm output Alex Bennée
9 siblings, 0 replies; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel
Cc: Philippe Mathieu-Daudé,
Paolo Bonzini, Alex Bennée, Richard Henderson
This will become useful shortly for providing more information about
output assembly inline. While there fix up the indenting and code
formatting in disas().
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
v2
- minor tweak to if(note){} fprintf(out,"\n") logig
---
include/disas/disas.h | 2 +-
include/exec/log.h | 4 ++--
accel/tcg/translate-all.c | 4 ++--
disas.c | 14 ++++++++++----
tcg/tcg.c | 4 ++--
5 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/include/disas/disas.h b/include/disas/disas.h
index 36c33f6f194..1b6e035e32d 100644
--- a/include/disas/disas.h
+++ b/include/disas/disas.h
@@ -7,7 +7,7 @@
#include "cpu.h"
/* Disassemble this for me please... (debugging). */
-void disas(FILE *out, void *code, unsigned long size);
+void disas(FILE *out, void *code, unsigned long size, const char *note);
void target_disas(FILE *out, CPUState *cpu, target_ulong code,
target_ulong size);
diff --git a/include/exec/log.h b/include/exec/log.h
index fcc7b9e00ba..3ed797c1c8c 100644
--- a/include/exec/log.h
+++ b/include/exec/log.h
@@ -56,13 +56,13 @@ static inline void log_target_disas(CPUState *cpu, target_ulong start,
rcu_read_unlock();
}
-static inline void log_disas(void *code, unsigned long size)
+static inline void log_disas(void *code, unsigned long size, const char *note)
{
QemuLogFile *logfile;
rcu_read_lock();
logfile = atomic_rcu_read(&qemu_logfile);
if (logfile) {
- disas(logfile->fd, code, size);
+ disas(logfile->fd, code, size, note);
}
rcu_read_unlock();
}
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index e4f703a7e6d..cdf58bb420e 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1800,7 +1800,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
size_t data_size = gen_code_size - code_size;
size_t i;
- log_disas(tb->tc.ptr, code_size);
+ log_disas(tb->tc.ptr, code_size, NULL);
for (i = 0; i < data_size; i += sizeof(tcg_target_ulong)) {
if (sizeof(tcg_target_ulong) == 8) {
@@ -1814,7 +1814,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
}
}
} else {
- log_disas(tb->tc.ptr, gen_code_size);
+ log_disas(tb->tc.ptr, gen_code_size, NULL);
}
qemu_log("\n");
qemu_log_flush();
diff --git a/disas.c b/disas.c
index 3937da61571..7e8692de301 100644
--- a/disas.c
+++ b/disas.c
@@ -586,7 +586,7 @@ char *plugin_disas(CPUState *cpu, uint64_t addr, size_t size)
}
/* Disassemble this for me please... (debugging). */
-void disas(FILE *out, void *code, unsigned long size)
+void disas(FILE *out, void *code, unsigned long size, const char *note)
{
uintptr_t pc;
int count;
@@ -674,10 +674,16 @@ void disas(FILE *out, void *code, unsigned long size)
for (pc = (uintptr_t)code; size > 0; pc += count, size -= count) {
fprintf(out, "0x%08" PRIxPTR ": ", pc);
count = print_insn(pc, &s.info);
- fprintf(out, "\n");
- if (count < 0)
- break;
+ if (note) {
+ fprintf(out, "\t\t%s", note);
+ note = NULL;
+ }
+ fprintf(out, "\n");
+ if (count < 0) {
+ break;
+ }
}
+
}
/* Look up symbol for debugging purpose. Returns "" if unknown. */
diff --git a/tcg/tcg.c b/tcg/tcg.c
index dd4b3d76844..a2268d9db0a 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -1092,7 +1092,7 @@ void tcg_prologue_init(TCGContext *s)
size_t data_size = prologue_size - code_size;
size_t i;
- log_disas(buf0, code_size);
+ log_disas(buf0, code_size, NULL);
for (i = 0; i < data_size; i += sizeof(tcg_target_ulong)) {
if (sizeof(tcg_target_ulong) == 8) {
@@ -1106,7 +1106,7 @@ void tcg_prologue_init(TCGContext *s)
}
}
} else {
- log_disas(buf0, prologue_size);
+ log_disas(buf0, prologue_size, NULL);
}
qemu_log("\n");
qemu_log_flush();
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* [PATCH v1 09/10] disas: add optional note support to cap_disas
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
` (7 preceding siblings ...)
2020-05-13 17:51 ` [PATCH v1 08/10] disas: include an optional note for the start of disassembly Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-13 17:51 ` [PATCH v1 10/10] translate-all: include guest address in out_asm output Alex Bennée
9 siblings, 0 replies; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel; +Cc: Philippe Mathieu-Daudé, Alex Bennée
Include support for outputting a note at the top of a chunk of
disassembly to capstone as well.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
v2
- always pass note down to cap_dump_insn
---
disas.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/disas.c b/disas.c
index 7e8692de301..45285d3f63f 100644
--- a/disas.c
+++ b/disas.c
@@ -260,7 +260,8 @@ static void cap_dump_insn_units(disassemble_info *info, cs_insn *insn,
}
}
-static void cap_dump_insn(disassemble_info *info, cs_insn *insn)
+static void cap_dump_insn(disassemble_info *info, cs_insn *insn,
+ const char *note)
{
fprintf_function print = info->fprintf_func;
int i, n, split;
@@ -281,7 +282,11 @@ static void cap_dump_insn(disassemble_info *info, cs_insn *insn)
}
/* Print the actual instruction. */
- print(info->stream, " %-8s %s\n", insn->mnemonic, insn->op_str);
+ print(info->stream, " %-8s %s", insn->mnemonic, insn->op_str);
+ if (note) {
+ print(info->stream, "\t\t%s", note);
+ }
+ print(info->stream, "\n");
/* Dump any remaining part of the insn on subsequent lines. */
for (i = split; i < n; i += split) {
@@ -313,7 +318,7 @@ static bool cap_disas_target(disassemble_info *info, uint64_t pc, size_t size)
size -= tsize;
while (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
- cap_dump_insn(info, insn);
+ cap_dump_insn(info, insn, NULL);
}
/* If the target memory is not consumed, go back for more... */
@@ -342,7 +347,8 @@ static bool cap_disas_target(disassemble_info *info, uint64_t pc, size_t size)
}
/* Disassemble SIZE bytes at CODE for the host. */
-static bool cap_disas_host(disassemble_info *info, void *code, size_t size)
+static bool cap_disas_host(disassemble_info *info, void *code, size_t size,
+ const char *note)
{
csh handle;
const uint8_t *cbuf;
@@ -358,7 +364,8 @@ static bool cap_disas_host(disassemble_info *info, void *code, size_t size)
pc = (uintptr_t)code;
while (cs_disasm_iter(handle, &cbuf, &size, &pc, insn)) {
- cap_dump_insn(info, insn);
+ cap_dump_insn(info, insn, note);
+ note = NULL;
}
if (size != 0) {
(*info->fprintf_func)(info->stream,
@@ -402,7 +409,7 @@ static bool cap_disas_monitor(disassemble_info *info, uint64_t pc, int count)
csize += tsize;
if (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
- cap_dump_insn(info, insn);
+ cap_dump_insn(info, insn, NULL);
if (--count <= 0) {
break;
}
@@ -416,7 +423,7 @@ static bool cap_disas_monitor(disassemble_info *info, uint64_t pc, int count)
#endif /* !CONFIG_USER_ONLY */
#else
# define cap_disas_target(i, p, s) false
-# define cap_disas_host(i, p, s) false
+# define cap_disas_host(i, p, s, n) false
# define cap_disas_monitor(i, p, c) false
# define cap_disas_plugin(i, p, c) false
#endif /* CONFIG_CAPSTONE */
@@ -664,7 +671,7 @@ void disas(FILE *out, void *code, unsigned long size, const char *note)
print_insn = print_insn_hppa;
#endif
- if (s.info.cap_arch >= 0 && cap_disas_host(&s.info, code, size)) {
+ if (s.info.cap_arch >= 0 && cap_disas_host(&s.info, code, size, note)) {
return;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* [PATCH v1 10/10] translate-all: include guest address in out_asm output
2020-05-13 17:51 [PATCH v1 00/10] testing and tcg tweaks Alex Bennée
` (8 preceding siblings ...)
2020-05-13 17:51 ` [PATCH v1 09/10] disas: add optional note support to cap_disas Alex Bennée
@ 2020-05-13 17:51 ` Alex Bennée
2020-05-21 14:04 ` Philippe Mathieu-Daudé
9 siblings, 1 reply; 19+ messages in thread
From: Alex Bennée @ 2020-05-13 17:51 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, Alex Bennée, Richard Henderson
We already have information about where each guest instructions
representation starts stored in the tcg_ctx->gen_insn_data so we can
rectify the PC for faults. We can re-use this information to annotate
the out_asm output with guest instruction address which makes it a bit
easier to work out where you are especially with longer blocks. A
minor wrinkle is that some instructions get optimised away so we have
to scan forward until we find some actual generated code.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
v1
- better logic for doing chunk at a time
- use new "note" facility to tag address
- rewrite the commit log
v2
- don't terminate gen_insn_end_off, trust your termination
conditions ;-)
---
accel/tcg/translate-all.c | 39 +++++++++++++++++++++++++++++++++------
1 file changed, 33 insertions(+), 6 deletions(-)
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index cdf58bb420e..42ce1dfcff7 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1794,14 +1794,43 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
if (qemu_loglevel_mask(CPU_LOG_TB_OUT_ASM) &&
qemu_log_in_addr_range(tb->pc)) {
FILE *logfile = qemu_log_lock();
+ int code_size, data_size = 0;
+ g_autoptr(GString) note = g_string_new("[tb header & initial instruction]");
+ size_t chunk_start = 0;
+ int insn = 0;
qemu_log("OUT: [size=%d]\n", gen_code_size);
if (tcg_ctx->data_gen_ptr) {
- size_t code_size = tcg_ctx->data_gen_ptr - tb->tc.ptr;
- size_t data_size = gen_code_size - code_size;
- size_t i;
+ code_size = tcg_ctx->data_gen_ptr - tb->tc.ptr;
+ data_size = gen_code_size - code_size;
+ } else {
+ code_size = gen_code_size;
+ }
- log_disas(tb->tc.ptr, code_size, NULL);
+ /* Dump header and the first instruction */
+ chunk_start = tcg_ctx->gen_insn_end_off[insn];
+ log_disas(tb->tc.ptr, chunk_start, note->str);
+ /*
+ * Dump each instruction chunk, wrapping up empty chunks into
+ * the next instruction. The whole array is offset so the
+ * first entry is the beginning of the 2nd instruction.
+ */
+ while (insn <= tb->icount && chunk_start < code_size) {
+ size_t chunk_end = tcg_ctx->gen_insn_end_off[insn];
+ if (chunk_end > chunk_start) {
+ g_string_printf(note, "[guest addr: " TARGET_FMT_lx "]",
+ tcg_ctx->gen_insn_data[insn][0]);
+ log_disas(tb->tc.ptr + chunk_start, chunk_end - chunk_start,
+ note->str);
+ chunk_start = chunk_end;
+ }
+ insn++;
+ }
+
+ /* Finally dump any data we may have after the block */
+ if (data_size) {
+ int i;
+ qemu_log(" data: [size=%d]\n", data_size);
for (i = 0; i < data_size; i += sizeof(tcg_target_ulong)) {
if (sizeof(tcg_target_ulong) == 8) {
qemu_log("0x%08" PRIxPTR ": .quad 0x%016" PRIx64 "\n",
@@ -1813,8 +1842,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
*(uint32_t *)(tcg_ctx->data_gen_ptr + i));
}
}
- } else {
- log_disas(tb->tc.ptr, gen_code_size, NULL);
}
qemu_log("\n");
qemu_log_flush();
--
2.20.1
^ permalink raw reply related [flat|nested] 19+ messages in thread* Re: [PATCH v1 10/10] translate-all: include guest address in out_asm output
2020-05-13 17:51 ` [PATCH v1 10/10] translate-all: include guest address in out_asm output Alex Bennée
@ 2020-05-21 14:04 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 19+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-05-21 14:04 UTC (permalink / raw)
To: Alex Bennée, qemu-devel; +Cc: Paolo Bonzini, Richard Henderson
Hi Alex,
On 5/13/20 7:51 PM, Alex Bennée wrote:
> We already have information about where each guest instructions
> representation starts stored in the tcg_ctx->gen_insn_data so we can
> rectify the PC for faults. We can re-use this information to annotate
> the out_asm output with guest instruction address which makes it a bit
> easier to work out where you are especially with longer blocks. A
> minor wrinkle is that some instructions get optimised away so we have
> to scan forward until we find some actual generated code.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>
> ---
> v1
> - better logic for doing chunk at a time
> - use new "note" facility to tag address
> - rewrite the commit log
> v2
> - don't terminate gen_insn_end_off, trust your termination
> conditions ;-)
> ---
> accel/tcg/translate-all.c | 39 +++++++++++++++++++++++++++++++++------
> 1 file changed, 33 insertions(+), 6 deletions(-)
>
> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
> index cdf58bb420e..42ce1dfcff7 100644
> --- a/accel/tcg/translate-all.c
> +++ b/accel/tcg/translate-all.c
> @@ -1794,14 +1794,43 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
> if (qemu_loglevel_mask(CPU_LOG_TB_OUT_ASM) &&
> qemu_log_in_addr_range(tb->pc)) {
> FILE *logfile = qemu_log_lock();
> + int code_size, data_size = 0;
> + g_autoptr(GString) note = g_string_new("[tb header & initial instruction]");
> + size_t chunk_start = 0;
> + int insn = 0;
> qemu_log("OUT: [size=%d]\n", gen_code_size);
> if (tcg_ctx->data_gen_ptr) {
> - size_t code_size = tcg_ctx->data_gen_ptr - tb->tc.ptr;
> - size_t data_size = gen_code_size - code_size;
> - size_t i;
> + code_size = tcg_ctx->data_gen_ptr - tb->tc.ptr;
> + data_size = gen_code_size - code_size;
> + } else {
> + code_size = gen_code_size;
> + }
>
> - log_disas(tb->tc.ptr, code_size, NULL);
> + /* Dump header and the first instruction */
> + chunk_start = tcg_ctx->gen_insn_end_off[insn];
> + log_disas(tb->tc.ptr, chunk_start, note->str);
>
> + /*
> + * Dump each instruction chunk, wrapping up empty chunks into
> + * the next instruction. The whole array is offset so the
> + * first entry is the beginning of the 2nd instruction.
> + */
> + while (insn <= tb->icount && chunk_start < code_size) {
> + size_t chunk_end = tcg_ctx->gen_insn_end_off[insn];
> + if (chunk_end > chunk_start) {
> + g_string_printf(note, "[guest addr: " TARGET_FMT_lx "]",
> + tcg_ctx->gen_insn_data[insn][0]);
> + log_disas(tb->tc.ptr + chunk_start, chunk_end - chunk_start,
> + note->str);
> + chunk_start = chunk_end;
> + }
> + insn++;
> + }
> +
> + /* Finally dump any data we may have after the block */
> + if (data_size) {
It seems we can simplify checking tcg_ctx->data_gen_ptr here, and
declaring data_size in this reduced scope. Doing so as a preliminary
patch makes the rest of this patch easier to review. What do you think?
> + int i;
> + qemu_log(" data: [size=%d]\n", data_size);
> for (i = 0; i < data_size; i += sizeof(tcg_target_ulong)) {
> if (sizeof(tcg_target_ulong) == 8) {
> qemu_log("0x%08" PRIxPTR ": .quad 0x%016" PRIx64 "\n",
> @@ -1813,8 +1842,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
> *(uint32_t *)(tcg_ctx->data_gen_ptr + i));
> }
> }
> - } else {
> - log_disas(tb->tc.ptr, gen_code_size, NULL);
> }
> qemu_log("\n");
> qemu_log_flush();
>
^ permalink raw reply [flat|nested] 19+ messages in thread