Re: [Qemu-devel] [PATCH] kvmvapic: align start address as well as size
On 03/15/2012 04:55 AM, Avi Kivity wrote: On 03/14/2012 10:33 PM, Anthony Liguori wrote: On 03/06/2012 09:50 AM, Avi Kivity wrote: The kvmvapic code remaps a section of ROM as RAM to allow the guest to maintain state there. It is careful to align the section size to a page boundary, to avoid creating subpages, but neglects to do the same for the start address. These leads to an assert later on when the memory core tries to create a page which is half RAM and half ROM. Fix by aligning the start address to a page boundary. This can be triggered by running qemu-system-x86_64 -enable-kvm -vga none. Signed-off-by: Avi Kivity Tested-by: Anthony Liguori Are you going to do a PULL request or do you want me to apply directly? I forgot all about it, sorry. No worries. I actually caught the bug in the original pull request but do to a bug in qemu-test, when I tried to bisect, things got weird and I mistakenly thought the real problem had been introduced earlier. Regards, Anthony Liguori
Re: [Qemu-devel] [PATCH] kvmvapic: align start address as well as size
On 03/14/2012 10:33 PM, Anthony Liguori wrote: > On 03/06/2012 09:50 AM, Avi Kivity wrote: >> The kvmvapic code remaps a section of ROM as RAM to allow the guest to >> maintain state there. It is careful to align the section size to a page >> boundary, to avoid creating subpages, but neglects to do the same for >> the start address. These leads to an assert later on when the memory >> core tries to create a page which is half RAM and half ROM. >> >> Fix by aligning the start address to a page boundary. >> >> This can be triggered by running qemu-system-x86_64 -enable-kvm -vga >> none. >> >> Signed-off-by: Avi Kivity > > Tested-by: Anthony Liguori > > Are you going to do a PULL request or do you want me to apply directly? I forgot all about it, sorry. -- error compiling committee.c: too many arguments to function
Re: [Qemu-devel] [PATCH] kvmvapic: align start address as well as size
On 03/06/2012 09:50 AM, Avi Kivity wrote: The kvmvapic code remaps a section of ROM as RAM to allow the guest to maintain state there. It is careful to align the section size to a page boundary, to avoid creating subpages, but neglects to do the same for the start address. These leads to an assert later on when the memory core tries to create a page which is half RAM and half ROM. Fix by aligning the start address to a page boundary. This can be triggered by running qemu-system-x86_64 -enable-kvm -vga none. Signed-off-by: Avi Kivity Applied. Thanks. Regards, Anthony Liguori --- hw/kvmvapic.c |4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/hw/kvmvapic.c b/hw/kvmvapic.c index 36ccfbc..e8bfeec 100644 --- a/hw/kvmvapic.c +++ b/hw/kvmvapic.c @@ -578,8 +578,10 @@ static void vapic_map_rom_writable(VAPICROMState *s) rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE; s->rom_size = rom_size; -/* We need to round up to avoid creating subpages +/* We need to round to avoid creating subpages * from which we cannot run code. */ +rom_size += rom_paddr& ~TARGET_PAGE_MASK; +rom_paddr&= TARGET_PAGE_MASK; rom_size = TARGET_PAGE_ALIGN(rom_size); memory_region_init_alias(&s->rom, "kvmvapic-rom", section.mr, rom_paddr,
Re: [Qemu-devel] [PATCH] kvmvapic: align start address as well as size
On 03/06/2012 09:50 AM, Avi Kivity wrote: The kvmvapic code remaps a section of ROM as RAM to allow the guest to maintain state there. It is careful to align the section size to a page boundary, to avoid creating subpages, but neglects to do the same for the start address. These leads to an assert later on when the memory core tries to create a page which is half RAM and half ROM. Fix by aligning the start address to a page boundary. This can be triggered by running qemu-system-x86_64 -enable-kvm -vga none. Signed-off-by: Avi Kivity Tested-by: Anthony Liguori Are you going to do a PULL request or do you want me to apply directly? Regards, Anthony Liguori --- hw/kvmvapic.c |4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/hw/kvmvapic.c b/hw/kvmvapic.c index 36ccfbc..e8bfeec 100644 --- a/hw/kvmvapic.c +++ b/hw/kvmvapic.c @@ -578,8 +578,10 @@ static void vapic_map_rom_writable(VAPICROMState *s) rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE; s->rom_size = rom_size; -/* We need to round up to avoid creating subpages +/* We need to round to avoid creating subpages * from which we cannot run code. */ +rom_size += rom_paddr& ~TARGET_PAGE_MASK; +rom_paddr&= TARGET_PAGE_MASK; rom_size = TARGET_PAGE_ALIGN(rom_size); memory_region_init_alias(&s->rom, "kvmvapic-rom", section.mr, rom_paddr,
Re: [Qemu-devel] [PATCH] kvmvapic: align start address as well as size
On 2012-03-06 16:50, Avi Kivity wrote: > The kvmvapic code remaps a section of ROM as RAM to allow the guest to > maintain state there. It is careful to align the section size to a page > boundary, to avoid creating subpages, but neglects to do the same for > the start address. These leads to an assert later on when the memory > core tries to create a page which is half RAM and half ROM. > > Fix by aligning the start address to a page boundary. > > This can be triggered by running qemu-system-x86_64 -enable-kvm -vga none. > > Signed-off-by: Avi Kivity > --- > hw/kvmvapic.c |4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/hw/kvmvapic.c b/hw/kvmvapic.c > index 36ccfbc..e8bfeec 100644 > --- a/hw/kvmvapic.c > +++ b/hw/kvmvapic.c > @@ -578,8 +578,10 @@ static void vapic_map_rom_writable(VAPICROMState *s) > rom_size = ram[rom_paddr + 2] * ROM_BLOCK_SIZE; > s->rom_size = rom_size; > > -/* We need to round up to avoid creating subpages > +/* We need to round to avoid creating subpages > * from which we cannot run code. */ > +rom_size += rom_paddr & ~TARGET_PAGE_MASK; > +rom_paddr &= TARGET_PAGE_MASK; > rom_size = TARGET_PAGE_ALIGN(rom_size); > > memory_region_init_alias(&s->rom, "kvmvapic-rom", section.mr, rom_paddr, Reviewed-by: Jan Kiszka -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
