Commit 284dc493 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: Take a 'struct page', not a pfn in kvm_is_zone_device_page() 



Operate on a 'struct page' instead of a pfn when checking if a page is a
ZONE_DEVICE page, and rename the helper accordingly.  Generally speaking,
KVM doesn't actually care about ZONE_DEVICE memory, i.e. shouldn't do
anything special for ZONE_DEVICE memory.  Rather, KVM wants to treat
ZONE_DEVICE memory like regular memory, and the need to identify
ZONE_DEVICE memory only arises as an exception to PG_reserved pages. In
other words, KVM should only ever check for ZONE_DEVICE memory after KVM
has already verified that there is a struct page associated with the pfn.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20220429010416.2788472-9-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b1624f99

arch/x86/kvm/mmu/mmu.c

+3 −2
Original line number Diff line number Diff line
@@ -2788,15 +2788,16 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) 
static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,

				  const struct kvm_memory_slot *slot)

{

	struct page *page = pfn_to_page(pfn);

	int level = PG_LEVEL_4K;

	unsigned long hva;

	unsigned long flags;

	int level = PG_LEVEL_4K;

	pgd_t pgd;

	p4d_t p4d;

	pud_t pud;

	pmd_t pmd;



	if (!PageCompound(pfn_to_page(pfn)) && !kvm_is_zone_device_pfn(pfn))

	if (!PageCompound(page) && !kvm_is_zone_device_page(page))

		return PG_LEVEL_4K;



	/*

include/linux/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -1571,7 +1571,7 @@ void kvm_arch_sync_events(struct kvm *kvm); 
int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu);



bool kvm_is_reserved_pfn(kvm_pfn_t pfn);

bool kvm_is_zone_device_pfn(kvm_pfn_t pfn);

bool kvm_is_zone_device_page(struct page *page);



struct kvm_irq_ack_notifier {

	struct hlist_node link;

virt/kvm/kvm_main.c

+4 −4
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ __weak void kvm_arch_guest_memory_reclaimed(struct kvm *kvm) 
{

}



bool kvm_is_zone_device_pfn(kvm_pfn_t pfn)

bool kvm_is_zone_device_page(struct page *page)

{

	/*

	 * The metadata used by is_zone_device_page() to determine whether or
@@ -176,10 +176,10 @@ bool kvm_is_zone_device_pfn(kvm_pfn_t pfn) 
	 * the device has been pinned, e.g. by get_user_pages().  WARN if the

	 * page_count() is zero to help detect bad usage of this helper.

	 */

	if (!pfn_valid(pfn) || WARN_ON_ONCE(!page_count(pfn_to_page(pfn))))

	if (WARN_ON_ONCE(!page_count(page)))

		return false;



	return is_zone_device_page(pfn_to_page(pfn));

	return is_zone_device_page(page);

}



bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
@@ -192,7 +192,7 @@ bool kvm_is_reserved_pfn(kvm_pfn_t pfn) 
	if (pfn_valid(pfn))

		return PageReserved(pfn_to_page(pfn)) &&

		       !is_zero_pfn(pfn) &&

		       !kvm_is_zone_device_pfn(pfn);

		       !kvm_is_zone_device_page(pfn_to_page(pfn));



	return true;

}