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b=LB8X6ImiwS+pRQhGYycXxWsTA/zbb8cKaDcKn7YY1YKr2eugSoSh8+GdnbU8Hm97m FiQzurLzDonqCYHy6zm2G6/LjiwrvFvk7hfm5tTxrdrmbmYGOGDTSdgoNb0r8l8ycw 7ULkXAgHk0+8nXyq2/BFo5fzyfI9gyQgfcBNj88H8uPF4CCODMBCEzlyvKyPE/mmKj oo8CZGVdYQMpVr1NgWCBveFt9ua7AkWHky6f0DmhzE8vepYpQl4m151HINIhTHBris SXMfxdDFveWSrSeRL/G+vWD2zz1/0Is5/lWKXpqNmO2r7UQBhyfpaO2tDPrxpwe7F/ xTZgbOC/BjT4Q== From: "Mike Rapoport (Microsoft)" Date: Wed, 02 Sep 2026 09:15:16 +0300 Subject: [PATCH 4/4] KVM: s390: Replace get_zeroed_page() with kzalloc() for sie_page2 and CMMA MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260902-s390-kvm-v1-4-3bc0986550b1@kernel.org> References: <20260902-s390-kvm-v1-0-3bc0986550b1@kernel.org> In-Reply-To: <20260902-s390-kvm-v1-0-3bc0986550b1@kernel.org> To: Christian Borntraeger , Claudio Imbrenda , Janosch Frank Cc: Alexander Gordeev , David Hildenbrand , Heiko Carstens , Mike Rapoport , Sven Schnelle , Vasily Gorbik , Vlastimil Babka , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org X-Mailer: b4 0.17-dev X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 81089180008 X-Stat-Signature: t1saer9io6mpz5dprmmytr4b4aebtyni X-HE-Tag: 1788329745-708923 X-HE-Meta: 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 b02GWwty 1DJ5AzmKGXDMC+lTI0ki4KaOzRBXijwt1yysTeEw+CLVvodz/JKM1Xfy5iM/MRWARc9g9HGNYOoIK1Y5MYRCug7gtN5Oy8zb7GHGpo9CYY/q05C0E5CUXQHWh2PLEY+boSKHqslKinP3Y6GLXwHRHkVDJeJ874GGtXzyrDDkV55pl/6w2zWGvX41lnGLA5fmOgMxSa5CaE8vKTG25uvrU0xV2XX2lEtAebAgxyIsh9lJmFHWgHPV+RKB7//xb01vfGya667wDM4AYbZWAb6kdkxJkbOjvk0lXVSJMrHB6Zh0hFRdpTYFk/09AcXvKEyfDc5Bn Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: kvm_arch_init_vm() allocates struct sie_page2 that holds the facility list and the crypto control block of a VM and kvm_s390_vcpu_setup_cmma() allocates the CMMA collaborative memory management block referenced by the SIE control block. Both are passed to the hardware as physical addresses and must be page aligned. kmalloc() guarantees that a power of two sized allocation is aligned to its size, so a PAGE_SIZE allocation is page aligned as well. These buffers can be allocated with kmalloc() as there's nothing special about them to go directly to the page allocator. kmalloc() provides a better API that does not require ugly casts and kfree() does not need to know the size of the freed object. Performance difference between kmalloc() and __get_free_pages() is not measurable as both allocators take an object/page from a per-CPU list for fast path allocations. For the slow path the performance is anyway determined by the amount of reclaim involved rather than by what allocator is used. The sie_page allocated in kvm_arch_vcpu_create() is left alone because it is mapped to userspace with virt_to_page() in kvm_arch_vcpu_fault() and therefore really needs a struct page. Replace use of get_zeroed_page() with kzalloc() and free_page() with kfree(). Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Assisted-by: copilot:claude-opus Signed-off-by: Mike Rapoport (Microsoft) --- arch/s390/kvm/s390/s390.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/s390/kvm/s390/s390.c b/arch/s390/kvm/s390/s390.c index b0839e887221e..8ec505060f8c0 100644 --- a/arch/s390/kvm/s390/s390.c +++ b/arch/s390/kvm/s390/s390.c @@ -3273,8 +3273,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) goto out_err; BUILD_BUG_ON(sizeof(struct sie_page2) != 4096); - kvm->arch.sie_page2 = - (struct sie_page2 *) get_zeroed_page(GFP_KERNEL_ACCOUNT | GFP_DMA); + kvm->arch.sie_page2 = kzalloc_obj(*kvm->arch.sie_page2, + GFP_KERNEL_ACCOUNT | GFP_DMA); if (!kvm->arch.sie_page2) goto out_err; @@ -3369,7 +3369,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) return 0; out_err: - free_page((unsigned long)kvm->arch.sie_page2); + kfree(kvm->arch.sie_page2); debug_unregister(kvm->arch.dbf); sca_dispose(kvm); KVM_EVENT(3, "creation of vm failed: %d", rc); @@ -3427,7 +3427,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm) mmu_notifier_unregister(&kvm->arch.pv.mmu_notifier, kvm->mm); debug_unregister(kvm->arch.dbf); - free_page((unsigned long)kvm->arch.sie_page2); + kfree(kvm->arch.sie_page2); kvm_s390_destroy_adapters(kvm); kvm_s390_clear_float_irqs(kvm); kvm_s390_vsie_destroy(kvm); @@ -3657,13 +3657,13 @@ static void kvm_s390_vcpu_crypto_setup(struct kvm_vcpu *vcpu) void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu) { if (vcpu->arch.sie_block->cbrlo) - free_page((unsigned long)phys_to_virt(vcpu->arch.sie_block->cbrlo)); + kfree(phys_to_virt(vcpu->arch.sie_block->cbrlo)); vcpu->arch.sie_block->cbrlo = 0; } int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu) { - void *cbrlo_page = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); + void *cbrlo_page = kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); if (!cbrlo_page) return -ENOMEM; -- 2.53.0