Commit c5f64c98 authored by David Hildenbrand's avatar David Hildenbrand Committed by Claudio Imbrenda
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KVM: s390: vsie: stop using page->index 



Let's stop using page->index, and instead use a field inside "struct
vsie_page" to hold that value. We have plenty of space left in there.

This is one part of stopping using "struct page" when working with vsie
pages. We place the "page_to_virt(page)" strategically, so the next
cleanups requires less churn.

Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: default avatarChristoph Schlameuss <schlameuss@linux.ibm.com>
Tested-by: default avatarChristoph Schlameuss <schlameuss@linux.ibm.com>
Message-ID: <20250107154344.1003072-3-david@redhat.com>
Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
parent 5f230f41

arch/s390/kvm/vsie.c

+18 −10
Original line number Diff line number Diff line
@@ -46,7 +46,13 @@ struct vsie_page { 
	gpa_t gvrd_gpa;				/* 0x0240 */

	gpa_t riccbd_gpa;			/* 0x0248 */

	gpa_t sdnx_gpa;				/* 0x0250 */

	__u8 reserved[0x0700 - 0x0258];		/* 0x0258 */

	/*

	 * guest address of the original SCB. Remains set for free vsie

	 * pages, so we can properly look them up in our addr_to_page

	 * radix tree.

	 */

	gpa_t scb_gpa;				/* 0x0258 */

	__u8 reserved[0x0700 - 0x0260];		/* 0x0260 */

	struct kvm_s390_crypto_cb crycb;	/* 0x0700 */

	__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE];	/* 0x0800 */

};
@@ -1362,9 +1368,10 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr) 
	page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);

	rcu_read_unlock();

	if (page) {

		vsie_page = page_to_virt(page);

		if (page_ref_inc_return(page) == 2) {

			if (page->index == addr)

				return page_to_virt(page);

			if (vsie_page->scb_gpa == addr)

				return vsie_page;

			/*

			 * We raced with someone reusing + putting this vsie

			 * page before we grabbed it.
@@ -1386,6 +1393,7 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr) 
			mutex_unlock(&kvm->arch.vsie.mutex);

			return ERR_PTR(-ENOMEM);

		}

		vsie_page = page_to_virt(page);

		page_ref_inc(page);

		kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;

		kvm->arch.vsie.page_count++;
@@ -1393,18 +1401,19 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr) 
		/* reuse an existing entry that belongs to nobody */

		while (true) {

			page = kvm->arch.vsie.pages[kvm->arch.vsie.next];

			vsie_page = page_to_virt(page);

			if (page_ref_inc_return(page) == 2)

				break;

			page_ref_dec(page);

			kvm->arch.vsie.next++;

			kvm->arch.vsie.next %= nr_vcpus;

		}

		if (page->index != ULONG_MAX)

		if (vsie_page->scb_gpa != ULONG_MAX)

			radix_tree_delete(&kvm->arch.vsie.addr_to_page,

					  page->index >> 9);

					  vsie_page->scb_gpa >> 9);

	}

	/* Mark it as invalid until it resides in the tree. */

	page->index = ULONG_MAX;

	vsie_page->scb_gpa = ULONG_MAX;



	/* Double use of the same address or allocation failure. */

	if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
@@ -1412,10 +1421,9 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr) 
		mutex_unlock(&kvm->arch.vsie.mutex);

		return NULL;

	}

	page->index = addr;

	vsie_page->scb_gpa = addr;

	mutex_unlock(&kvm->arch.vsie.mutex);



	vsie_page = page_to_virt(page);

	memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));

	release_gmap_shadow(vsie_page);

	vsie_page->fault_addr = 0;
@@ -1507,9 +1515,9 @@ void kvm_s390_vsie_destroy(struct kvm *kvm) 
		vsie_page = page_to_virt(page);

		release_gmap_shadow(vsie_page);

		/* free the radix tree entry */

		if (page->index != ULONG_MAX)

		if (vsie_page->scb_gpa != ULONG_MAX)

			radix_tree_delete(&kvm->arch.vsie.addr_to_page,

					  page->index >> 9);

					  vsie_page->scb_gpa >> 9);

		__free_page(page);

	}

	kvm->arch.vsie.page_count = 0;