| Message ID | 20240915233117.478169-1-gshan@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | hostmem: Apply merge property after the memory region is initialized | expand |
[PATCH] hostmem: Apply merge property after the memory region is initialized Test on 4k and 64k basic page size aarch64 The patches work well on my Ampere host. The test results are as expected. # /home/test/qemu.main/build/qemu-system-aarch64 \ -accel kvm -machine virt -cpu host \ -object memory-backend-ram,id=mem-memN0,size=4096M,merge=off Tested-by: Zhenyu Zhang <zhenyzha@redhat.com> On Mon, Sep 16, 2024 at 7:31 AM Gavin Shan <gshan@redhat.com> wrote: > > The semantic change has been introduced by commit 5becdc0ab0 ("hostmem: > simplify the code for merge and dump properties") even it clarifies that > no senmatic change has been introduced. After the commit, the merge > property can be applied even the corresponding memory region isn't > initialized yet. This leads to crash dump by the following command > lines. > > # /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ > -accel kvm -machine virt -cpu host \ > -object memory-backend-ram,id=mem-memN0,size=4096M,merge=off > : > qemu-system-aarch64: ../system/memory.c:2419: memory_region_get_ram_ptr: \ > Assertion `mr->ram_block' failed. > > Fix it by applying the merge property only when the memory region is > initialized. > > Fixes: 5becdc0ab083 ("hostmem: simplify the code for merge and dump properties") > Reported-by: Zhenyu Zhang <zhenyzha@redhat.com> > Signed-off-by: Gavin Shan <gshan@redhat.com> > --- > backends/hostmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/backends/hostmem.c b/backends/hostmem.c > index 4e5576a4ad..181446626a 100644 > --- a/backends/hostmem.c > +++ b/backends/hostmem.c > @@ -178,7 +178,7 @@ static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp) > return; > } > > - if (!host_memory_backend_mr_inited(backend) && > + if (host_memory_backend_mr_inited(backend) && > value != backend->merge) { > void *ptr = memory_region_get_ram_ptr(&backend->mr); > uint64_t sz = memory_region_size(&backend->mr); > -- > 2.45.2 >
On 16.09.24 01:31, Gavin Shan wrote: > The semantic change has been introduced by commit 5becdc0ab0 ("hostmem: > simplify the code for merge and dump properties") even it clarifies that > no senmatic change has been introduced. After the commit, the merge > property can be applied even the corresponding memory region isn't > initialized yet. This leads to crash dump by the following command > lines. > > # /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ > -accel kvm -machine virt -cpu host \ > -object memory-backend-ram,id=mem-memN0,size=4096M,merge=off > : > qemu-system-aarch64: ../system/memory.c:2419: memory_region_get_ram_ptr: \ > Assertion `mr->ram_block' failed. > > Fix it by applying the merge property only when the memory region is > initialized. > > Fixes: 5becdc0ab083 ("hostmem: simplify the code for merge and dump properties") > Reported-by: Zhenyu Zhang <zhenyzha@redhat.com> > Signed-off-by: Gavin Shan <gshan@redhat.com> > --- > backends/hostmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/backends/hostmem.c b/backends/hostmem.c > index 4e5576a4ad..181446626a 100644 > --- a/backends/hostmem.c > +++ b/backends/hostmem.c > @@ -178,7 +178,7 @@ static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp) > return; > } > > - if (!host_memory_backend_mr_inited(backend) && > + if (host_memory_backend_mr_inited(backend) && > value != backend->merge) { > void *ptr = memory_region_get_ram_ptr(&backend->mr); > uint64_t sz = memory_region_size(&backend->mr); Thanks, queued to https://github.com/davidhildenbrand/qemu.git mem-next
diff --git a/backends/hostmem.c b/backends/hostmem.c index 4e5576a4ad..181446626a 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -178,7 +178,7 @@ static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp) return; } - if (!host_memory_backend_mr_inited(backend) && + if (host_memory_backend_mr_inited(backend) && value != backend->merge) { void *ptr = memory_region_get_ram_ptr(&backend->mr); uint64_t sz = memory_region_size(&backend->mr);
The semantic change has been introduced by commit 5becdc0ab0 ("hostmem: simplify the code for merge and dump properties") even it clarifies that no senmatic change has been introduced. After the commit, the merge property can be applied even the corresponding memory region isn't initialized yet. This leads to crash dump by the following command lines. # /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ -accel kvm -machine virt -cpu host \ -object memory-backend-ram,id=mem-memN0,size=4096M,merge=off : qemu-system-aarch64: ../system/memory.c:2419: memory_region_get_ram_ptr: \ Assertion `mr->ram_block' failed. Fix it by applying the merge property only when the memory region is initialized. Fixes: 5becdc0ab083 ("hostmem: simplify the code for merge and dump properties") Reported-by: Zhenyu Zhang <zhenyzha@redhat.com> Signed-off-by: Gavin Shan <gshan@redhat.com> --- backends/hostmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)