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Commit 75a18122 authored by Alexander Yarygin's avatar Alexander Yarygin Committed by Christian Borntraeger
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KVM: s390: Optimize paths where get_vcpu_asce() is invoked 



During dynamic address translation the get_vcpu_asce()
function can be invoked several times. It's ok for usual modes, but will
be slow if CPUs are in AR mode. Let's call the get_vcpu_asce() once and
pass the result to the called functions.

Signed-off-by: default avatarAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 8ae04b8f

arch/s390/kvm/gaccess.c

+12 −13
Original line number Diff line number Diff line
@@ -330,6 +330,7 @@ static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val) 
 * @vcpu: virtual cpu

 * @gva: guest virtual address

 * @gpa: points to where guest physical (absolute) address should be stored

 * @asce: effective asce

 * @write: indicates if access is a write access

 *

 * Translate a guest virtual address into a guest absolute address by means
@@ -345,7 +346,8 @@ static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val) 
 *	      by the architecture

 */

static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,

				     unsigned long *gpa, int write)

				     unsigned long *gpa, const union asce asce,

				     int write)

{

	union vaddress vaddr = {.addr = gva};

	union raddress raddr = {.addr = gva};
@@ -354,12 +356,10 @@ static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva, 
	union ctlreg0 ctlreg0;

	unsigned long ptr;

	int edat1, edat2;

	union asce asce;



	ctlreg0.val = vcpu->arch.sie_block->gcr[0];

	edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8);

	edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78);

	asce.val = get_vcpu_asce(vcpu);

	if (asce.r)

		goto real_address;

	ptr = asce.origin * 4096;
@@ -506,15 +506,14 @@ static inline int is_low_address(unsigned long ga) 
	return (ga & ~0x11fful) == 0;

}



static int low_address_protection_enabled(struct kvm_vcpu *vcpu)

static int low_address_protection_enabled(struct kvm_vcpu *vcpu,

					  const union asce asce)

{

	union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};

	psw_t *psw = &vcpu->arch.sie_block->gpsw;

	union asce asce;



	if (!ctlreg0.lap)

		return 0;

	asce.val = get_vcpu_asce(vcpu);

	if (psw_bits(*psw).t && asce.p)

		return 0;

	return 1;
@@ -536,7 +535,7 @@ enum { 


static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga,

			    unsigned long *pages, unsigned long nr_pages,

			    int write)

			    const union asce asce, int write)

{

	struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;

	psw_t *psw = &vcpu->arch.sie_block->gpsw;
@@ -547,7 +546,7 @@ static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, 
	tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;

	tec_bits->fsi = write ? FSI_STORE : FSI_FETCH;

	tec_bits->as = psw_bits(*psw).as;

	lap_enabled = low_address_protection_enabled(vcpu);

	lap_enabled = low_address_protection_enabled(vcpu, asce);

	while (nr_pages) {

		ga = kvm_s390_logical_to_effective(vcpu, ga);

		tec_bits->addr = ga >> PAGE_SHIFT;
@@ -557,7 +556,7 @@ static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga, 
		}

		ga &= PAGE_MASK;

		if (psw_bits(*psw).t) {

			rc = guest_translate(vcpu, ga, pages, write);

			rc = guest_translate(vcpu, ga, pages, asce, write);

			if (rc < 0)

				return rc;

			if (rc == PGM_PROTECTION)
@@ -604,7 +603,7 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data, 
	need_ipte_lock = psw_bits(*psw).t && !asce.r;

	if (need_ipte_lock)

		ipte_lock(vcpu);

	rc = guest_page_range(vcpu, ga, pages, nr_pages, write);

	rc = guest_page_range(vcpu, ga, pages, nr_pages, asce, write);

	for (idx = 0; idx < nr_pages && !rc; idx++) {

		gpa = *(pages + idx) + (ga & ~PAGE_MASK);

		_len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
@@ -671,16 +670,16 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar, 
	tec->as = psw_bits(*psw).as;

	tec->fsi = write ? FSI_STORE : FSI_FETCH;

	tec->addr = gva >> PAGE_SHIFT;

	if (is_low_address(gva) && low_address_protection_enabled(vcpu)) {

	asce.val = get_vcpu_asce(vcpu);

	if (is_low_address(gva) && low_address_protection_enabled(vcpu, asce)) {

		if (write) {

			rc = pgm->code = PGM_PROTECTION;

			return rc;

		}

	}



	asce.val = get_vcpu_asce(vcpu);

	if (psw_bits(*psw).t && !asce.r) {	/* Use DAT? */

		rc = guest_translate(vcpu, gva, gpa, write);

		rc = guest_translate(vcpu, gva, gpa, asce, write);

		if (rc > 0) {

			if (rc == PGM_PROTECTION)

				tec->b61 = 1;