On Wed, Aug 22, 2012 at 07:55:31AM +0200, Alexander Graf wrote: > > On 22.08.2012, at 06:59, David Gibson wrote: > > > cpu_physical_memory_write_rom(), despite the name, can also be used to > > write images into RAM - and will often be used that way if the machine > > uses load_image_targphys() into RAM addresses. > > > > However, cpu_physical_memory_write_rom(), unlike cpu_physical_memory_rw() > > does invalidate any cached TBs which might be affected by the region > > written. > > > > This was breaking reset (under full emu) on the pseries machine - we loaded > > our firmware image into RAM, and while executing it rewrite the code at > > the entry point (correctly causing a TB invalidate/refresh). When we > > reset the firmware image was reloaded, but the TB from the rewrite was > > still active and caused us to get an illegal instruction trap. > > > > This patch fixes the bug by duplicating the tb invalidate code from > > cpu_physical_memory_rw() in cpu_physical_memory_write_rom(). > > > > Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> > > --- > > exec.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/exec.c b/exec.c > > index 5834766..eff40d7 100644 > > --- a/exec.c > > +++ b/exec.c > > @@ -3523,6 +3523,13 @@ void > > cpu_physical_memory_write_rom(target_phys_addr_t addr, > > /* ROM/RAM case */ > > ptr = qemu_get_ram_ptr(addr1); > > memcpy(ptr, buf, l); > > + if (!cpu_physical_memory_is_dirty(addr1)) { > > + /* invalidate code */ > > + tb_invalidate_phys_page_range(addr1, addr1 + l, 0); > > + /* set dirty bit */ > > + cpu_physical_memory_set_dirty_flags( > > + addr1, (0xff & ~CODE_DIRTY_FLAG)); > > + } > > Can't we just call cpu_physical_memory_rw in the RAM case? The > function only tries to not do MMIO accesses on ROM pages, right?
Maybe. It's not clear at all to me what cases cpu_physical_memory_write_rom() is supposed to be for, as opposed to just using cpu_physical_memory_rw(). -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson