diff mbox

[5/5] KVM: VMX: conditionally disable 2M pages

Message ID 20090609213312.998029496@amt.cnet (mailing list archive)
State New, archived
Headers show

Commit Message

Marcelo Tosatti June 9, 2009, 9:30 p.m. UTC 
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 <mtosatti@redhat.com>



--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

Avi Kivity June 10, 2009, 9:18 a.m. UTC | #1 
Marcelo Tosatti wrote:
> 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.
>
> 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)
> @@ -1184,6 +1186,10 @@ int __kvm_set_memory_region(struct kvm *
>  		if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE - 1))
>  			for (i = 0; i < largepages; ++i)
>  				new.lpage_info[i].write_count = 1;
> +
> +		if (largepages_disabled)
> +			for (i = 0; i < largepages; ++i)
> +				new.lpage_info[i].write_count = 1;
>  	}
>   

Please reuse the loop above, it's exactly the same (think of 1GB pages).
diff mbox

Patch

Index: kvm/arch/x86/kvm/vmx.c
===================================================================
--- kvm.orig/arch/x86/kvm/vmx.c
+++ kvm/arch/x86/kvm/vmx.c
@@ -1369,6 +1369,9 @@  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
@@ -203,6 +203,7 @@  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)
@@ -1184,6 +1186,10 @@  int __kvm_set_memory_region(struct kvm *
 		if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE - 1))
 			for (i = 0; i < largepages; ++i)
 				new.lpage_info[i].write_count = 1;
+
+		if (largepages_disabled)
+			for (i = 0; i < largepages; ++i)
+				new.lpage_info[i].write_count = 1;
 	}
 
 	/* Allocate page dirty bitmap if needed */
@@ -1294,6 +1300,12 @@  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;