diff options
| author | Marcelo Tosatti <marcelo@kvack.org> | 2007-12-12 10:46:12 -0500 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-01-30 17:53:22 +0200 |
| commit | 2bacc55c7c3c61e356aef06b9a319b4cee90b519 (patch) | |
| tree | 8a1860bbcfe62970353b71260887449c334f5477 /drivers/kvm | |
| parent | 62b9abaaf8423a3a38b938831b3b8431a6607ad8 (diff) | |
KVM: MMU: emulated cmpxchg8b should be atomic on i386
Emulate cmpxchg8b atomically on i386. This is required to avoid a guest
pte walker from seeing a splitted write.
[avi: make it compile]
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'drivers/kvm')
| -rw-r--r-- | drivers/kvm/x86.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c index 9db4e3242b6..3b79684a3c0 100644 --- a/drivers/kvm/x86.c +++ b/drivers/kvm/x86.c @@ -25,6 +25,7 @@ #include <linux/vmalloc.h> #include <linux/module.h> #include <linux/mman.h> +#include <linux/highmem.h> #include <asm/uaccess.h> #include <asm/msr.h> @@ -1674,6 +1675,31 @@ static int emulator_cmpxchg_emulated(unsigned long addr, 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; + + if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK)) + goto emul_write; + + val = *(u64 *)new; + page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT); + addr = kmap_atomic(page, KM_USER0); + set_64bit((u64 *)(addr + offset_in_page(gpa)), val); + kunmap_atomic(addr, KM_USER0); + kvm_release_page_dirty(page); + } +emul_write: +#endif + return emulator_write_emulated(addr, new, bytes, vcpu); } |