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KVM: s390: Minor refactor of base/ext facility lists

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Directly use the size of the arrays instead of going through the
indirection of kvm_s390_fac_size().
Don't use magic number for the number of entries in the non hypervisor
managed facility bit mask list.
Make the constraint of that number on kvm_s390_fac_base obvious.
Get rid of implicit double anding of stfle_fac_list.

Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Co-developed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260612-vsie-alter-stfle-fac-v4-1-74f0e1559929@linux.ibm.com>
This commit is contained in:
Nina Schoetterl-Glausch 2026-06-12 14:23:01 +02:00 committed by Claudio Imbrenda
parent c7dda3d0f8
commit 20dcfaf2d3
1 changed files with 19 additions and 25 deletions
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44
arch/s390/kvm/kvm-s390.c
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@ -237,33 +237,25 @@ static int async_destroy = 1;
module_param(async_destroy, int, 0444);
MODULE_PARM_DESC(async_destroy, "Asynchronous destroy for protected guests");
/*
* 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
#define HMFAI_DWORDS 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 };
static unsigned long kvm_s390_fac_base[HMFAI_DWORDS] = { FACILITIES_KVM };
static_assert(ARRAY_SIZE(((long[]){ FACILITIES_KVM })) <= HMFAI_DWORDS);
static_assert(ARRAY_SIZE(kvm_s390_fac_base) <= S390_ARCH_FAC_MASK_SIZE_U64);
static_assert(ARRAY_SIZE(kvm_s390_fac_base) <= S390_ARCH_FAC_LIST_SIZE_U64);
static_assert(ARRAY_SIZE(kvm_s390_fac_base) <= ARRAY_SIZE(stfle_fac_list));
/*
* 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(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(stfle_fac_list));
return SIZE_INTERNAL;
}
static const unsigned long kvm_s390_fac_ext[] = { FACILITIES_KVM_CPUMODEL };
static_assert(ARRAY_SIZE(kvm_s390_fac_ext) <= S390_ARCH_FAC_MASK_SIZE_U64);
static_assert(ARRAY_SIZE(kvm_s390_fac_ext) <= S390_ARCH_FAC_LIST_SIZE_U64);
static_assert(ARRAY_SIZE(kvm_s390_fac_ext) <= ARRAY_SIZE(stfle_fac_list));
/* available cpu features supported by kvm */
static DECLARE_BITMAP(kvm_s390_available_cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS);
@ -3249,13 +3241,16 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm->arch.sie_page2->kvm = kvm;
kvm->arch.model.fac_list = kvm->arch.sie_page2->fac_list;
for (i = 0; i < kvm_s390_fac_size(); i++) {
for (i = 0; i < ARRAY_SIZE(kvm_s390_fac_base); i++) {
kvm->arch.model.fac_mask[i] = stfle_fac_list[i] &
(kvm_s390_fac_base[i] |
kvm_s390_fac_ext[i]);
kvm_s390_fac_base[i];
kvm->arch.model.fac_list[i] = stfle_fac_list[i] &
kvm_s390_fac_base[i];
}
for (i = 0; i < ARRAY_SIZE(kvm_s390_fac_ext); i++) {
kvm->arch.model.fac_mask[i] |= stfle_fac_list[i] &
kvm_s390_fac_ext[i];
}
kvm->arch.model.subfuncs = kvm_s390_available_subfunc;
/* we are always in czam mode - even on pre z14 machines */
@ -5878,9 +5873,8 @@ static int __init kvm_s390_init(void)
pr_info("Disabling 2G hugepage support, since 1M hugepage support is not enabled.\n");
}
for (i = 0; i < 16; i++)
kvm_s390_fac_base[i] |=
stfle_fac_list[i] & nonhyp_mask(i);
for (i = 0; i < HMFAI_DWORDS; i++)
kvm_s390_fac_base[i] |= nonhyp_mask(i);
r = __kvm_s390_init();
if (r)