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Commit 54dee993 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

KVM: VMX: conditionally disable 2M pages 



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.

[avi: s/largepages_disabled/largepages_enabled/ to avoid negative logic]

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 68f89400

arch/x86/kvm/vmx.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -1381,6 +1381,9 @@ static __init int hardware_setup(void) 
	if (!cpu_has_vmx_tpr_shadow())

	if (!cpu_has_vmx_tpr_shadow())

		kvm_x86_ops->update_cr8_intercept = NULL;

		kvm_x86_ops->update_cr8_intercept = NULL;





	if (enable_ept && !cpu_has_vmx_ept_2m_page())

		kvm_disable_largepages();



	return alloc_kvm_area();

	return alloc_kvm_area();

}

}

include/linux/kvm_host.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -224,6 +224,7 @@ int kvm_arch_set_memory_region(struct kvm *kvm, 
				struct kvm_userspace_memory_region *mem,

				struct kvm_userspace_memory_region *mem,

				struct kvm_memory_slot old,

				struct kvm_memory_slot old,

				int user_alloc);

				int user_alloc);

void kvm_disable_largepages(void);

void kvm_arch_flush_shadow(struct kvm *kvm);

void kvm_arch_flush_shadow(struct kvm *kvm);

gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);

gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);

struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);

struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);

virt/kvm/kvm_main.c

+12 −2
Original line number Original line Diff line number Diff line
@@ -85,6 +85,8 @@ static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl, 




static bool kvm_rebooting;

static bool kvm_rebooting;





static bool largepages_enabled = true;



#ifdef KVM_CAP_DEVICE_ASSIGNMENT

#ifdef KVM_CAP_DEVICE_ASSIGNMENT

static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,

static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,

						      int assigned_dev_id)

						      int assigned_dev_id)
@@ -1174,9 +1176,11 @@ int __kvm_set_memory_region(struct kvm *kvm, 
		ugfn = new.userspace_addr >> PAGE_SHIFT;

		ugfn = new.userspace_addr >> PAGE_SHIFT;

		/*

		/*

		 * If the gfn and userspace address are not aligned wrt each

		 * 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_enabled)

			for (i = 0; i < largepages; ++i)

			for (i = 0; i < largepages; ++i)

				new.lpage_info[i].write_count = 1;

				new.lpage_info[i].write_count = 1;

	}

	}
@@ -1291,6 +1295,12 @@ int kvm_get_dirty_log(struct kvm *kvm, 
	return r;

	return r;

}

}





void kvm_disable_largepages(void)

{

	largepages_enabled = false;

}

EXPORT_SYMBOL_GPL(kvm_disable_largepages);



int is_error_page(struct page *page)

int is_error_page(struct page *page)

{

{

	return page == bad_page;

	return page == bad_page;