Re: [Qemu-devel] Re: [PATCH] Fix segfault with ram_size 4095M without kvm
On Wed, Jan 05, 2011 at 01:04:51PM -0600, Ryan Harper wrote: * Ryan Harper ry...@us.ibm.com [2011-01-04 09:49]: * Aurelien Jarno aurel...@aurel32.net [2010-12-25 16:37]: On Wed, Dec 08, 2010 at 04:27:45PM -0200, Luiz Capitulino wrote: On Wed, 08 Dec 2010 12:23:12 -0600 Anthony Liguori aligu...@linux.vnet.ibm.com wrote: On 12/08/2010 12:01 PM, Luiz Capitulino wrote: Currently, x86_64-softmmu qemu segfaults when trying to use 4095M memsize. This patch adds a simple check and error message (much like the 2047 limit on 32-bit hosts) on ram_size in the control path after we determine we're not using kvm Upstream qemu-kvm is affected if using the -no-kvm option; this patch address the segfault there as well. Signed-off-by: Ryan Harperry...@us.ibm.com Signed-off-by: Aurelien Jarnoaurel...@aurel32.net --- NOTE: this patch was applied in the v0.12.x branch, but it seems it got lost for master No, it was intentional. We should fix the segv, this is not a known limitation but rather a bug. A TCG bug, I presume? Do you have more details about this issue and how to reproduce it? At the time of the bug, it was something simple like: qemu-system-x86_64 -m 4097 -hda /dev/null we'd get an imediate segfault. As you say, I'm not seeing it now on current git; I'll see about bisecting to see if we did get a fix for the issue. I attempted to bisect, but there a couple commits around where the issue was fixed that broke git bisect =( That narrowed it down to about 5 commits to check. This the last git commit where I can reproduce the segfault with the above test case (qemu invocation). commit 0aef4261ac0ec9089ade0e3a92f986cb4ba7317e Author: Aurelien Jarno aurel...@aurel32.net Date: Thu Mar 11 21:29:42 2010 +0100 target-ppc: fix evsrwu and evsrws (second try) Signed-off-by: Aurelien Jarno aurel...@aurel32.net The next 4 commits don't compile so they are untest-able: commit 14f24e1465edc44b9b4d89fbbea66e06088154e1 - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 commit 7bc7b099dfa38a856b1bc892c0f9f3d6fe28e170 - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 commit b9f83121a13153536d886305414b540460c34508 - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 commit 5270589032f450ae7c3448730855aa18ff68ccff - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 And this commit compiles and the test case no longer segfaults. So I'd say things are fixed at this point. commit 5cd2c5b6ad75c46d40118ac67c0c09d4e7930a65 - compiles and issue is no longer present. - ./configure --target-list=x86_64-softmmu make clean make sudo x86_64-softmmu/qemu-syem-x86_64 -L pc-bios -hda /dev/null -m 4097 It's more likely this commit which fixes the bug. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel32.net
Re: [Qemu-devel] Re: [PATCH] Fix segfault with ram_size 4095M without kvm
* Ryan Harper ry...@us.ibm.com [2011-01-04 09:49]: * Aurelien Jarno aurel...@aurel32.net [2010-12-25 16:37]: On Wed, Dec 08, 2010 at 04:27:45PM -0200, Luiz Capitulino wrote: On Wed, 08 Dec 2010 12:23:12 -0600 Anthony Liguori aligu...@linux.vnet.ibm.com wrote: On 12/08/2010 12:01 PM, Luiz Capitulino wrote: Currently, x86_64-softmmu qemu segfaults when trying to use 4095M memsize. This patch adds a simple check and error message (much like the 2047 limit on 32-bit hosts) on ram_size in the control path after we determine we're not using kvm Upstream qemu-kvm is affected if using the -no-kvm option; this patch address the segfault there as well. Signed-off-by: Ryan Harperry...@us.ibm.com Signed-off-by: Aurelien Jarnoaurel...@aurel32.net --- NOTE: this patch was applied in the v0.12.x branch, but it seems it got lost for master No, it was intentional. We should fix the segv, this is not a known limitation but rather a bug. A TCG bug, I presume? Do you have more details about this issue and how to reproduce it? At the time of the bug, it was something simple like: qemu-system-x86_64 -m 4097 -hda /dev/null we'd get an imediate segfault. As you say, I'm not seeing it now on current git; I'll see about bisecting to see if we did get a fix for the issue. I attempted to bisect, but there a couple commits around where the issue was fixed that broke git bisect =( That narrowed it down to about 5 commits to check. This the last git commit where I can reproduce the segfault with the above test case (qemu invocation). commit 0aef4261ac0ec9089ade0e3a92f986cb4ba7317e Author: Aurelien Jarno aurel...@aurel32.net Date: Thu Mar 11 21:29:42 2010 +0100 target-ppc: fix evsrwu and evsrws (second try) Signed-off-by: Aurelien Jarno aurel...@aurel32.net The next 4 commits don't compile so they are untest-able: commit 14f24e1465edc44b9b4d89fbbea66e06088154e1 - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 commit 7bc7b099dfa38a856b1bc892c0f9f3d6fe28e170 - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 commit b9f83121a13153536d886305414b540460c34508 - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 commit 5270589032f450ae7c3448730855aa18ff68ccff - fails to build with: - ./configure --target-list=x86_64-softmmu make clean make /home/rharper/work/git/qemu/exec.c: In function 'phys_page_find_alloc': /home/rharper/work/git/qemu/exec.c:341: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS /home/rharper/work/git/qemu/exec.c: In function 'phys_page_for_each': /home/rharper/work/git/qemu/exec.c:1670: error: #error unsupported TARGET_PHYS_ADDR_SPACE_BITS make[1]: *** [exec.o] Error 1 make: *** [subdir-x86_64-softmmu] Error 2 And this commit compiles and the test case no longer segfaults. So I'd say things are fixed at this point. commit 5cd2c5b6ad75c46d40118ac67c0c09d4e7930a65 - compiles and issue is no longer present. - ./configure --target-list=x86_64-softmmu make clean make sudo x86_64-softmmu/qemu-syem-x86_64 -L pc-bios -hda /dev/null -m 4097 -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx ry...@us.ibm.com
Re: [Qemu-devel] Re: [PATCH] Fix segfault with ram_size 4095M without kvm
* Aurelien Jarno aurel...@aurel32.net [2010-12-25 16:37]: On Wed, Dec 08, 2010 at 04:27:45PM -0200, Luiz Capitulino wrote: On Wed, 08 Dec 2010 12:23:12 -0600 Anthony Liguori aligu...@linux.vnet.ibm.com wrote: On 12/08/2010 12:01 PM, Luiz Capitulino wrote: Currently, x86_64-softmmu qemu segfaults when trying to use 4095M memsize. This patch adds a simple check and error message (much like the 2047 limit on 32-bit hosts) on ram_size in the control path after we determine we're not using kvm Upstream qemu-kvm is affected if using the -no-kvm option; this patch address the segfault there as well. Signed-off-by: Ryan Harperry...@us.ibm.com Signed-off-by: Aurelien Jarnoaurel...@aurel32.net --- NOTE: this patch was applied in the v0.12.x branch, but it seems it got lost for master No, it was intentional. We should fix the segv, this is not a known limitation but rather a bug. A TCG bug, I presume? Do you have more details about this issue and how to reproduce it? At the time of the bug, it was something simple like: qemu-system-x86_64 -m 4097 -hda /dev/null we'd get an imediate segfault. As you say, I'm not seeing it now on current git; I'll see about bisecting to see if we did get a fix for the issue. Support for more than 4GB of memory has been added a few years ago, and I am not able to reproduce the problem anymore (I have booted a 64-bit guest with 6GB of RAM, and make sure the guest use the whole memory). I guess TCG itself is fine, but there might be a bug in the MMU emulation in some cases. I also noticed that now i386-softmmu has been artificially limited to 2047MB. Tthis configuration used to support up to 64GB of RAM (PAE) on 64-bit hosts. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel33.net -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx ry...@us.ibm.com
[Qemu-devel] Re: [PATCH] Fix segfault with ram_size 4095M without kvm
On Wed, Dec 08, 2010 at 04:27:45PM -0200, Luiz Capitulino wrote: On Wed, 08 Dec 2010 12:23:12 -0600 Anthony Liguori aligu...@linux.vnet.ibm.com wrote: On 12/08/2010 12:01 PM, Luiz Capitulino wrote: Currently, x86_64-softmmu qemu segfaults when trying to use 4095M memsize. This patch adds a simple check and error message (much like the 2047 limit on 32-bit hosts) on ram_size in the control path after we determine we're not using kvm Upstream qemu-kvm is affected if using the -no-kvm option; this patch address the segfault there as well. Signed-off-by: Ryan Harperry...@us.ibm.com Signed-off-by: Aurelien Jarnoaurel...@aurel32.net --- NOTE: this patch was applied in the v0.12.x branch, but it seems it got lost for master No, it was intentional. We should fix the segv, this is not a known limitation but rather a bug. A TCG bug, I presume? Do you have more details about this issue and how to reproduce it? Support for more than 4GB of memory has been added a few years ago, and I am not able to reproduce the problem anymore (I have booted a 64-bit guest with 6GB of RAM, and make sure the guest use the whole memory). I guess TCG itself is fine, but there might be a bug in the MMU emulation in some cases. I also noticed that now i386-softmmu has been artificially limited to 2047MB. Tthis configuration used to support up to 64GB of RAM (PAE) on 64-bit hosts. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel33.net
[Qemu-devel] Re: [PATCH] Fix segfault with ram_size 4095M without kvm
On 12/08/2010 12:01 PM, Luiz Capitulino wrote:
Currently, x86_64-softmmu qemu segfaults when trying to use 4095M memsize.
This patch adds a simple check and error message (much like the 2047 limit on
32-bit hosts) on ram_size in the control path after we determine we're
not using kvm
Upstream qemu-kvm is affected if using the -no-kvm option; this patch address
the segfault there as well.
Signed-off-by: Ryan Harperry...@us.ibm.com
Signed-off-by: Aurelien Jarnoaurel...@aurel32.net
---
NOTE: this patch was applied in the v0.12.x branch, but it seems it got
lost for master
No, it was intentional. We should fix the segv, this is not a known
limitation but rather a bug.
Regards,
Anthony Liguori
vl.c |6 ++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/vl.c b/vl.c
index 2dbb6db..bb9c21c 100644
--- a/vl.c
+++ b/vl.c
@@ -5792,6 +5792,12 @@ int main(int argc, char **argv, char **envp)
fprintf(stderr, failed to initialize KVM\n);
exit(1);
}
+} else {
+/* without kvm enabled, we can only support 4095 MB RAM */
+if (ram_size (4095UL 20)) {
+fprintf(stderr, qemu: without kvm support at most 4095 MB RAM can be
simulated\n);
+exit(1);
+}
}
if (qemu_init_main_loop()) {
[Qemu-devel] Re: [PATCH] Fix segfault with ram_size 4095M without kvm
On Wed, 08 Dec 2010 12:23:12 -0600
Anthony Liguori aligu...@linux.vnet.ibm.com wrote:
On 12/08/2010 12:01 PM, Luiz Capitulino wrote:
Currently, x86_64-softmmu qemu segfaults when trying to use 4095M memsize.
This patch adds a simple check and error message (much like the 2047 limit
on
32-bit hosts) on ram_size in the control path after we determine we're
not using kvm
Upstream qemu-kvm is affected if using the -no-kvm option; this patch
address
the segfault there as well.
Signed-off-by: Ryan Harperry...@us.ibm.com
Signed-off-by: Aurelien Jarnoaurel...@aurel32.net
---
NOTE: this patch was applied in the v0.12.x branch, but it seems it got
lost for master
No, it was intentional. We should fix the segv, this is not a known
limitation but rather a bug.
A TCG bug, I presume?
Regards,
Anthony Liguori
vl.c |6 ++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/vl.c b/vl.c
index 2dbb6db..bb9c21c 100644
--- a/vl.c
+++ b/vl.c
@@ -5792,6 +5792,12 @@ int main(int argc, char **argv, char **envp)
fprintf(stderr, failed to initialize KVM\n);
exit(1);
}
+} else {
+/* without kvm enabled, we can only support 4095 MB RAM */
+if (ram_size (4095UL 20)) {
+fprintf(stderr, qemu: without kvm support at most 4095 MB RAM
can be simulated\n);
+exit(1);
+}
}
if (qemu_init_main_loop()) {
[Qemu-devel] Re: [PATCH] Fix segfault with ram_size 4095M without kvm
On 12/08/2010 12:27 PM, Luiz Capitulino wrote:
On Wed, 08 Dec 2010 12:23:12 -0600
Anthony Liguorialigu...@linux.vnet.ibm.com wrote:
On 12/08/2010 12:01 PM, Luiz Capitulino wrote:
Currently, x86_64-softmmu qemu segfaults when trying to use 4095M memsize.
This patch adds a simple check and error message (much like the 2047 limit on
32-bit hosts) on ram_size in the control path after we determine we're
not using kvm
Upstream qemu-kvm is affected if using the -no-kvm option; this patch address
the segfault there as well.
Signed-off-by: Ryan Harperry...@us.ibm.com
Signed-off-by: Aurelien Jarnoaurel...@aurel32.net
---
NOTE: this patch was applied in the v0.12.x branch, but it seems it got
lost for master
No, it was intentional. We should fix the segv, this is not a known
limitation but rather a bug.
A TCG bug, I presume?
Dunno, that's why we shouldn't just paper over it.
Regards,
Anthony Liguori
Regards,
Anthony Liguori
vl.c |6 ++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/vl.c b/vl.c
index 2dbb6db..bb9c21c 100644
--- a/vl.c
+++ b/vl.c
@@ -5792,6 +5792,12 @@ int main(int argc, char **argv, char **envp)
fprintf(stderr, failed to initialize KVM\n);
exit(1);
}
+} else {
+/* without kvm enabled, we can only support 4095 MB RAM */
+if (ram_size (4095UL 20)) {
+fprintf(stderr, qemu: without kvm support at most 4095 MB RAM can be
simulated\n);
+exit(1);
+}
}
if (qemu_init_main_loop()) {
