From mboxrd@z Thu Jan 1 00:00:00 1970 From: Izik Eidus Subject: Re: [PATCH 3/3] add support for change_pte mmu notifiers Date: Sat, 12 Sep 2009 09:41:10 +0300 Message-ID: <4AAB4286.9070303@redhat.com> References: <1252600738-9456-1-git-send-email-ieidus@redhat.com> <1252600738-9456-2-git-send-email-ieidus@redhat.com> <1252600738-9456-3-git-send-email-ieidus@redhat.com> <1252600738-9456-4-git-send-email-ieidus@redhat.com> <20090911212418.GC6244@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: avi@redhat.com, kvm@vger.kernel.org, aarcange@redhat.com To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:6310 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753584AbZILGc5 (ORCPT ); Sat, 12 Sep 2009 02:32:57 -0400 Received: from int-mx04.intmail.prod.int.phx2.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.17]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n8C6X0P5017417 for ; Sat, 12 Sep 2009 02:33:01 -0400 In-Reply-To: <20090911212418.GC6244@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: > On Thu, Sep 10, 2009 at 07:38:58PM +0300, Izik Eidus wrote: > >> this is needed for kvm if it want ksm to directly map pages into its >> shadow page tables. >> >> Signed-off-by: Izik Eidus >> --- >> arch/x86/include/asm/kvm_host.h | 1 + >> arch/x86/kvm/mmu.c | 70 ++++++++++++++++++++++++++++++++++---- >> virt/kvm/kvm_main.c | 14 ++++++++ >> 3 files changed, 77 insertions(+), 8 deletions(-) >> >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index 6046e6f..594d131 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -797,6 +797,7 @@ asmlinkage void kvm_handle_fault_on_reboot(void); >> #define KVM_ARCH_WANT_MMU_NOTIFIER >> int kvm_unmap_hva(struct kvm *kvm, unsigned long hva); >> int kvm_age_hva(struct kvm *kvm, unsigned long hva); >> +void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); >> int cpuid_maxphyaddr(struct kvm_vcpu *vcpu); >> int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu); >> int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu); >> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c >> index a7151b8..3fd19f2 100644 >> --- a/arch/x86/kvm/mmu.c >> +++ b/arch/x86/kvm/mmu.c >> @@ -282,6 +282,11 @@ static pfn_t spte_to_pfn(u64 pte) >> return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; >> } >> >> +static pte_t ptep_val(pte_t *ptep) >> +{ >> + return *ptep; >> +} >> + >> static gfn_t pse36_gfn_delta(u32 gpte) >> { >> int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT; >> @@ -748,7 +753,8 @@ static int rmap_write_protect(struct kvm *kvm, u64 gfn) >> return write_protected; >> } >> >> -static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp) >> +static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp, >> + unsigned long data) >> { >> u64 *spte; >> int need_tlb_flush = 0; >> @@ -763,8 +769,48 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp) >> return need_tlb_flush; >> } >> >> +static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, >> + unsigned long data) >> +{ >> + int need_flush = 0; >> + u64 *spte, new_spte; >> + pte_t *ptep = (pte_t *)data; >> + pfn_t new_pfn; >> + >> + new_pfn = pte_pfn(ptep_val(ptep)); >> + spte = rmap_next(kvm, rmapp, NULL); >> + while (spte) { >> + BUG_ON(!is_shadow_present_pte(*spte)); >> + rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte); >> + need_flush = 1; >> + if (pte_write(ptep_val(ptep))) { >> + rmap_remove(kvm, spte); >> + __set_spte(spte, shadow_trap_nonpresent_pte); >> + spte = rmap_next(kvm, rmapp, NULL); >> + } else { >> + new_spte = *spte &~ (PT64_BASE_ADDR_MASK); >> + new_spte |= new_pfn << PAGE_SHIFT; >> + >> + if (!pte_write(ptep_val(ptep))) { >> + new_spte &= ~PT_WRITABLE_MASK; >> + new_spte &= ~SPTE_HOST_WRITEABLE; >> + if (is_writeble_pte(*spte)) >> + kvm_set_pfn_dirty(spte_to_pfn(*spte)); >> + } >> + __set_spte(spte, new_spte); >> + spte = rmap_next(kvm, rmapp, spte); >> + } >> + } >> + if (need_flush) >> + kvm_flush_remote_tlbs(kvm); >> + >> + return 0; >> +} >> + >> static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, >> - int (*handler)(struct kvm *kvm, unsigned long *rmapp)) >> + unsigned long data, >> + int (*handler)(struct kvm *kvm, unsigned long *rmapp, >> + unsigned long data)) >> { >> int i, j; >> int retval = 0; >> @@ -786,13 +832,15 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, >> if (hva >= start && hva < end) { >> gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT; >> >> - retval |= handler(kvm, &memslot->rmap[gfn_offset]); >> + retval |= handler(kvm, &memslot->rmap[gfn_offset], >> + data); >> >> for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) { >> int idx = gfn_offset; >> idx /= KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL + j); >> retval |= handler(kvm, >> - &memslot->lpage_info[j][idx].rmap_pde); >> + &memslot->lpage_info[j][idx].rmap_pde, >> + data); >> > > If change_pte is called to modify a largepage pte, and the shadow has > that largepage mapped with 4k sptes, you'll set the wrong pfn. That is, > the patch does not attempt to handle different page sizes properly. > > So either disable change_pte updates to non-4k host vmas (making it > explictly it does not handle different pagesizes), or handle largepages > properly, although i don't see any use for change_pte or largepage > mappings? > change_pte doesn't get called on 4k pages... So adding commet to this function saying it is working just on 4k pages would be enough ?