From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: [patch 5/5] KVM: VMX: conditionally disable 2M pages Date: Thu, 11 Jun 2009 11:02:29 -0300 Message-ID: <20090611140417.013188677@localhost.localdomain> References: <20090611140224.457657937@localhost.localdomain> Cc: kvm@vger.kernel.org, Marcelo Tosatti To: avi@redhat.com Return-path: Received: from mx2.redhat.com ([66.187.237.31]:55345 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750808AbZFKOFX (ORCPT ); Thu, 11 Jun 2009 10:05:23 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n5BE5QL4026882 for ; Thu, 11 Jun 2009 10:05:26 -0400 In-Reply-To: <4A307819.6010503@redhat.com> Content-Disposition: inline; filename=disable-2m-pages-vmx Sender: kvm-owner@vger.kernel.org List-ID: Disable usage of 2M pages if VMX_EPT_2MB_PAGE_BIT (bit 16) is clear in MSR_IA32_VMX_EPT_VPID_CAP and EPT is enabled. Signed-off-by: Marcelo Tosatti Index: kvm/arch/x86/kvm/vmx.c =================================================================== --- kvm.orig/arch/x86/kvm/vmx.c +++ kvm/arch/x86/kvm/vmx.c @@ -1393,6 +1393,9 @@ static __init int hardware_setup(void) if (!cpu_has_vmx_tpr_shadow()) kvm_x86_ops->update_cr8_intercept = NULL; + if (enable_ept && !cpu_has_vmx_ept_2m_page()) + kvm_disable_largepages(); + return alloc_kvm_area(); } Index: kvm/include/linux/kvm_host.h =================================================================== --- kvm.orig/include/linux/kvm_host.h +++ kvm/include/linux/kvm_host.h @@ -219,6 +219,7 @@ int kvm_arch_set_memory_region(struct kv struct kvm_userspace_memory_region *mem, struct kvm_memory_slot old, int user_alloc); +void kvm_disable_largepages(void); void kvm_arch_flush_shadow(struct kvm *kvm); gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn); struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn); Index: kvm/virt/kvm/kvm_main.c =================================================================== --- kvm.orig/virt/kvm/kvm_main.c +++ kvm/virt/kvm/kvm_main.c @@ -85,6 +85,8 @@ static long kvm_vcpu_ioctl(struct file * static bool kvm_rebooting; +static bool largepages_disabled = false; + #ifdef KVM_CAP_DEVICE_ASSIGNMENT static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head, int assigned_dev_id) @@ -1171,9 +1173,11 @@ int __kvm_set_memory_region(struct kvm * ugfn = new.userspace_addr >> PAGE_SHIFT; /* * If the gfn and userspace address are not aligned wrt each - * other, disable large page support for this slot + * other, or if explicitly asked to, disable large page + * support for this slot */ - if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE - 1)) + if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE - 1) || + largepages_disabled) for (i = 0; i < largepages; ++i) new.lpage_info[i].write_count = 1; } @@ -1286,6 +1290,12 @@ out: return r; } +void kvm_disable_largepages(void) +{ + largepages_disabled = true; +} +EXPORT_SYMBOL_GPL(kvm_disable_largepages); + int is_error_page(struct page *page) { return page == bad_page; --