Marcelo Tosatti wrote: > Emulate cmpxchg8b atomically on i386. This is required to avoid a guest > pte walker from seeing a splitted write. > > Signed-off-by: Marcelo Tosatti <[EMAIL PROTECTED]> > > diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c > index 9db4e32..d58d795 100644 > --- a/drivers/kvm/x86.c > +++ b/drivers/kvm/x86.c > @@ -1674,6 +1674,33 @@ static int emulator_cmpxchg_emulated(uns > reported = 1; > printk(KERN_WARNING "kvm: emulating exchange as write\n"); > } > +#ifndef CONFIG_X86_64 > + /* guests cmpxchg8b have to be emulated atomically */ > + if (bytes == 8) { > + gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr); > + struct page *page; > + char *addr; > + u64 *val; > + > + if (gpa == UNMAPPED_GVA || > + (gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE) > + goto emul_write; > + > + val = (u64 *)new; > + page = gfn_to_page(page, gpa >> PAGE_SHIFT); > + addr = kmap_atomic(page, KM_USER0); > + addr += offset_in_page(gpa); > + > + set_64bit((unsigned long long *)addr, val); > + > + kunmap_atomic(page, KM_USER0); > + kvm_release_page_dirty(page); > + > + return X86EMUL_CONTINUE; > + } > +#endif > + > +emul_write: > return emulator_write_emulated(addr, new, bytes, vcpu); > } >
Won't the compiler complain when it sees an unreferenced label? Also, we should handle the page boundary crossing case (probably by just emulating as a write and crosssing fingers). -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel