The page table walk is coded as an infinite loop, with a special case on the last pte.
Code it as an ordinary loop with a termination condition on the last pte (large page or walk length exhausted), and put the last pte handling code after the loop where it belongs. Signed-off-by: Avi Kivity <[email protected]> --- arch/x86/kvm/paging_tmpl.h | 60 +++++++++++++++++++--------------------------- 1 file changed, 25 insertions(+), 35 deletions(-) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 8f6c59f..1b4c14d 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -171,12 +171,15 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, gfn_t table_gfn; unsigned index, pt_access, pte_access; gpa_t pte_gpa; - bool eperm, last_gpte; + bool eperm; int offset; const int write_fault = access & PFERR_WRITE_MASK; const int user_fault = access & PFERR_USER_MASK; const int fetch_fault = access & PFERR_FETCH_MASK; u16 errcode = 0; + gpa_t real_gpa; + gfn_t gfn; + u32 ac; trace_kvm_mmu_pagetable_walk(addr, access); retry_walk: @@ -197,12 +200,16 @@ retry_walk: ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) || (mmu->get_cr3(vcpu) & CR3_NONPAE_RESERVED_BITS) == 0); - pt_access = ACC_ALL; + pt_access = pte_access = ACC_ALL; + ++walker->level; - for (;;) { + do { gfn_t real_gfn; unsigned long host_addr; + pt_access &= pte_access; + --walker->level; + index = PT_INDEX(addr, walker->level); table_gfn = gpte_to_gfn(pte); @@ -239,39 +246,8 @@ retry_walk: pte_access = pt_access & gpte_access(vcpu, pte); - last_gpte = FNAME(is_last_gpte)(walker, vcpu, mmu, pte); - walker->ptes[walker->level - 1] = pte; - - if (last_gpte) { - int lvl = walker->level; - gpa_t real_gpa; - gfn_t gfn; - u32 ac; - - gfn = gpte_to_gfn_lvl(pte, lvl); - gfn += (addr & PT_LVL_OFFSET_MASK(lvl)) >> PAGE_SHIFT; - - if (PTTYPE == 32 && - walker->level == PT_DIRECTORY_LEVEL && - is_cpuid_PSE36()) - gfn += pse36_gfn_delta(pte); - - ac = write_fault | fetch_fault | user_fault; - - real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn), - ac); - if (real_gpa == UNMAPPED_GVA) - return 0; - - walker->gfn = real_gpa >> PAGE_SHIFT; - - break; - } - - pt_access &= pte_access; - --walker->level; - } + } while (!FNAME(is_last_gpte)(walker, vcpu, mmu, pte)); eperm |= permission_fault(mmu, pte_access, access); if (unlikely(eperm)) { @@ -279,6 +255,20 @@ retry_walk: goto error; } + gfn = gpte_to_gfn_lvl(pte, walker->level); + gfn += (addr & PT_LVL_OFFSET_MASK(walker->level)) >> PAGE_SHIFT; + + if (PTTYPE == 32 && walker->level == PT_DIRECTORY_LEVEL && is_cpuid_PSE36()) + gfn += pse36_gfn_delta(pte); + + ac = write_fault | fetch_fault | user_fault; + + real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn), ac); + if (real_gpa == UNMAPPED_GVA) + return 0; + + walker->gfn = real_gpa >> PAGE_SHIFT; + if (!write_fault) protect_clean_gpte(&pte_access, pte); -- 1.7.12 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
