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Commit c3b9e3e1 authored by Christian Borntraeger's avatar Christian Borntraeger
Browse files

KVM: s390: implement CPU model only facilities 



Some facilities should only be provided to the guest, if they are
enabled by a CPU model. This allows us to avoid capabilities and
to simply fall back to the cpumodel for deciding about a facility
without enabling it for older QEMUs or QEMUs without a CPU
model.

Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent f07afa04

arch/s390/kvm/kvm-s390.c

+34 −19
Original line number Diff line number Diff line
@@ -152,13 +152,33 @@ static int nested; 
module_param(nested, int, S_IRUGO);

MODULE_PARM_DESC(nested, "Nested virtualization support");



/* upper facilities limit for kvm */

unsigned long kvm_s390_fac_list_mask[16] = { FACILITIES_KVM };



unsigned long kvm_s390_fac_list_mask_size(void)

/*

 * For now we handle at most 16 double words as this is what the s390 base

 * kernel handles and stores in the prefix page. If we ever need to go beyond

 * this, this requires changes to code, but the external uapi can stay.

 */

#define SIZE_INTERNAL 16



/*

 * Base feature mask that defines default mask for facilities. Consists of the

 * defines in FACILITIES_KVM and the non-hypervisor managed bits.

 */

static unsigned long kvm_s390_fac_base[SIZE_INTERNAL] = { FACILITIES_KVM };

/*

 * Extended feature mask. Consists of the defines in FACILITIES_KVM_CPUMODEL

 * and defines the facilities that can be enabled via a cpu model.

 */

static unsigned long kvm_s390_fac_ext[SIZE_INTERNAL] = { FACILITIES_KVM_CPUMODEL };



static unsigned long kvm_s390_fac_size(void)

{

	BUILD_BUG_ON(ARRAY_SIZE(kvm_s390_fac_list_mask) > S390_ARCH_FAC_MASK_SIZE_U64);

	return ARRAY_SIZE(kvm_s390_fac_list_mask);

	BUILD_BUG_ON(SIZE_INTERNAL > S390_ARCH_FAC_MASK_SIZE_U64);

	BUILD_BUG_ON(SIZE_INTERNAL > S390_ARCH_FAC_LIST_SIZE_U64);

	BUILD_BUG_ON(SIZE_INTERNAL * sizeof(unsigned long) >

		sizeof(S390_lowcore.stfle_fac_list));



	return SIZE_INTERNAL;

}



/* available cpu features supported by kvm */
@@ -1967,20 +1987,15 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) 
	if (!kvm->arch.sie_page2)

		goto out_err;



	/* Populate the facility mask initially. */

	memcpy(kvm->arch.model.fac_mask, S390_lowcore.stfle_fac_list,

	       sizeof(S390_lowcore.stfle_fac_list));

	for (i = 0; i < S390_ARCH_FAC_LIST_SIZE_U64; i++) {

		if (i < kvm_s390_fac_list_mask_size())

			kvm->arch.model.fac_mask[i] &= kvm_s390_fac_list_mask[i];

		else

			kvm->arch.model.fac_mask[i] = 0UL;

	}



	/* Populate the facility list initially. */

	kvm->arch.model.fac_list = kvm->arch.sie_page2->fac_list;

	memcpy(kvm->arch.model.fac_list, kvm->arch.model.fac_mask,

	       S390_ARCH_FAC_LIST_SIZE_BYTE);



	for (i = 0; i < kvm_s390_fac_size(); i++) {

		kvm->arch.model.fac_mask[i] = S390_lowcore.stfle_fac_list[i] &

					      (kvm_s390_fac_base[i] |

					       kvm_s390_fac_ext[i]);

		kvm->arch.model.fac_list[i] = S390_lowcore.stfle_fac_list[i] &

					      kvm_s390_fac_base[i];

	}



	/* we are always in czam mode - even on pre z14 machines */

	set_kvm_facility(kvm->arch.model.fac_mask, 138);
@@ -4044,7 +4059,7 @@ static int __init kvm_s390_init(void) 
	}



	for (i = 0; i < 16; i++)

		kvm_s390_fac_list_mask[i] |=

		kvm_s390_fac_base[i] |=

			S390_lowcore.stfle_fac_list[i] & nonhyp_mask(i);



	return kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);

arch/s390/kvm/kvm-s390.h

+0 −2
Original line number Diff line number Diff line
@@ -294,8 +294,6 @@ void exit_sie(struct kvm_vcpu *vcpu); 
void kvm_s390_sync_request(int req, struct kvm_vcpu *vcpu);

int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu);

void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu);

unsigned long kvm_s390_fac_list_mask_size(void);

extern unsigned long kvm_s390_fac_list_mask[];

void kvm_s390_set_cpu_timer(struct kvm_vcpu *vcpu, __u64 cputm);

__u64 kvm_s390_get_cpu_timer(struct kvm_vcpu *vcpu);

arch/s390/tools/gen_facilities.c

+20 −0
Original line number Diff line number Diff line
@@ -62,6 +62,13 @@ static struct facility_def facility_defs[] = { 
		}

	},

	{

		/*

		 * FACILITIES_KVM contains the list of facilities that are part

		 * of the default facility mask and list that are passed to the

		 * initial CPU model. If no CPU model is used, this, together

		 * with the non-hypervisor managed bits, is the maximum list of

		 * guest facilities supported by KVM.

		 */

		.name = "FACILITIES_KVM",

		.bits = (int[]){

			0,  /* N3 instructions */
@@ -89,6 +96,19 @@ static struct facility_def facility_defs[] = { 
			-1  /* END */

		}

	},

	{

		/*

		 * FACILITIES_KVM_CPUMODEL contains the list of facilities

		 * that can be enabled by CPU model code if the host supports

		 * it. These facilities are not passed to the guest without

		 * CPU model support.

		 */



		.name = "FACILITIES_KVM_CPUMODEL",

		.bits = (int[]){

			-1  /* END */

		}

	},

};



static void print_facility_list(struct facility_def *def)