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 <ieidus@xxxxxxxxxx>
> ---
> 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?
> }
> }
> }
> @@ -802,10 +850,16 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
>
> int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
> {
> - return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
> + return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
> +}
> +
> +void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
> +{
> + kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
> }
>
> -static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
> +static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
> + unsigned long data)
> {
> u64 *spte;
> int young = 0;
> @@ -841,13 +895,13 @@ static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
> gfn = unalias_gfn(vcpu->kvm, gfn);
> rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
>
> - kvm_unmap_rmapp(vcpu->kvm, rmapp);
> + kvm_unmap_rmapp(vcpu->kvm, rmapp, 0);
> kvm_flush_remote_tlbs(vcpu->kvm);
> }
>
> int kvm_age_hva(struct kvm *kvm, unsigned long hva)
> {
> - return kvm_handle_hva(kvm, hva, kvm_age_rmapp);
> + return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp);
> }
>
> #ifdef MMU_DEBUG
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index cb7966f..c9a88af 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -240,6 +240,19 @@ static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
>
> }
>
> +static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
> + struct mm_struct *mm,
> + unsigned long address,
> + pte_t pte)
> +{
> + struct kvm *kvm = mmu_notifier_to_kvm(mn);
> +
> + spin_lock(&kvm->mmu_lock);
> + kvm->mmu_notifier_seq++;
> + kvm_set_spte_hva(kvm, address, pte);
> + spin_unlock(&kvm->mmu_lock);
> +}
> +
> static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
> struct mm_struct *mm,
> unsigned long start,
> @@ -319,6 +332,7 @@ static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
> .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
> .invalidate_range_end = kvm_mmu_notifier_invalidate_range_end,
> .clear_flush_young = kvm_mmu_notifier_clear_flush_young,
> + .change_pte = kvm_mmu_notifier_change_pte,
> .release = kvm_mmu_notifier_release,
> };
> #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
> --
> 1.5.6.5
>
> --
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