diff options
| author | Gleb Natapov <gleb@redhat.com> | 2013-08-05 11:07:11 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2013-08-07 15:57:37 +0200 |
| commit | 61719a8fff3da865cdda57dd62974e561e16315d (patch) | |
| tree | 61cec4f5d28d4a7ce092884c0cd1c0f117de132c /arch/x86 | |
| parent | d8089baca4f6895ce9c7bdabd2fca48a23feee79 (diff) | |
nEPT: Support shadow paging for guest paging without A/D bits
Some guest paging modes do not support A/D bits. Add support for such
modes in shadow page code. For such modes PT_GUEST_DIRTY_MASK,
PT_GUEST_ACCESSED_MASK, PT_GUEST_DIRTY_SHIFT and PT_GUEST_ACCESSED_SHIFT
should be set to zero.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 83702a68e987..656f7fae312a 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -92,6 +92,10 @@ static inline void FNAME(protect_clean_gpte)(unsigned *access, unsigned gpte) { unsigned mask; + /* dirty bit is not supported, so no need to track it */ + if (!PT_GUEST_DIRTY_MASK) + return; + BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK); mask = (unsigned)~ACC_WRITE_MASK; @@ -147,7 +151,8 @@ static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu, if (!FNAME(is_present_gpte)(gpte)) goto no_present; - if (!(gpte & PT_GUEST_ACCESSED_MASK)) + /* if accessed bit is not supported prefetch non accessed gpte */ + if (PT_GUEST_ACCESSED_MASK && !(gpte & PT_GUEST_ACCESSED_MASK)) goto no_present; return false; @@ -178,6 +183,10 @@ static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu, gfn_t table_gfn; int ret; + /* dirty/accessed bits are not supported, so no need to update them */ + if (!PT_GUEST_DIRTY_MASK) + return 0; + for (level = walker->max_level; level >= walker->level; --level) { pte = orig_pte = walker->ptes[level - 1]; table_gfn = walker->table_gfn[level - 1]; @@ -316,8 +325,9 @@ retry_walk: FNAME(protect_clean_gpte)(&pte_access, pte); else /* - * On a write fault, fold the dirty bit into accessed_dirty by - * shifting it one place right. + * On a write fault, fold the dirty bit into accessed_dirty. + * For modes without A/D bits support accessed_dirty will be + * always clear. */ accessed_dirty &= pte >> (PT_GUEST_DIRTY_SHIFT - PT_GUEST_ACCESSED_SHIFT); |