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b=PYMp5XZs0RSikeOmuwhKduqniWT3hGFAXvR0qtGbALX9yosr5KePfNaVKRg2SYiMw McPUiTok5nieRhEXBdSvYsbnohtBT6eIH7uo8rKYD0KjrtCe939rzxcAOi7eKhdzlK /J5jg6Cs50eL9nyAeDEwkb+kVAhGHqCa9HptydJc36ezW2aYQTWAVT2zJ3s2BvoZJ9 ZU0XIXucyOWL9vLlOdtrggfum95IivONi/zf+Z5UuI5qMUYm2kprd8LNgSvJL3nSRh l7+Y6tYXYBM614JIt91OPc+lOS0AklR7KTb2Ql8XHR7x5kg4z9UfusC95OUyZpMewN kXn39hX7a6AbA== From: "Mike Rapoport (Microsoft)" Date: Sun, 06 Sep 2026 11:27:11 +0300 Subject: [PATCH v2 3/4] KVM: s390: Replace get_zeroed_page() with kzalloc() for the GIB MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260906-s390-kvm-v2-3-2cf6434e6646@kernel.org> References: <20260906-s390-kvm-v2-0-2cf6434e6646@kernel.org> In-Reply-To: <20260906-s390-kvm-v2-0-2cf6434e6646@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: rspam07 X-Rspamd-Queue-Id: 8CE29C0004 X-Stat-Signature: 7r8yhepbi8td6iequnic5xbghwykdtfd X-HE-Tag: 1788683254-461255 X-HE-Meta: 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 fByYN2RN ehTtNSvnNLe1AbHvChAF03Tu7oTTnkfngPeg7AMKC0e+6tXLRjYcRITHw2k5LER4clGXdUgYigqe9iXIEXG72JQuEcu/TxJwS8zrREGD+NsanBAQKYAIwR8x+GfPor+EFTz/Bzud36z5YDtIjkdROA7tcVjoFb+vpPm8ge1pWSQ5C9EwzV/7FzNzAtk9L+RrpCi4un4wnCHnszJ0wqkCD2B0kOdHse+V8W/XWQmi1mqgbKkS8Udt4YU/SfUcbI/QR0zYEYDdAI2DIinWTXz+SFPcCtHFCcesIWZ98s/76p05kKDcxV80blfi87Kl5Rxs7bZ5F Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: kvm_s390_gib_init() allocates the guest information block (GIB). The GIB is passed to the hardware as a physical address 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. This buffer can be allocated with kmalloc() as there's nothing special about it 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. 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/interrupt.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/s390/kvm/s390/interrupt.c b/arch/s390/kvm/s390/interrupt.c index 0381ae9817035..02065fb8d053e 100644 --- a/arch/s390/kvm/s390/interrupt.c +++ b/arch/s390/kvm/s390/interrupt.c @@ -3689,7 +3689,7 @@ void kvm_s390_gib_destroy(void) } chsc_sgib(0); unregister_adapter_interrupt(&gib_alert_irq); - free_page((unsigned long)gib); + kfree(gib); gib = NULL; } @@ -3703,7 +3703,7 @@ int __init kvm_s390_gib_init(u8 nisc) goto out; } - gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL_ACCOUNT | GFP_DMA); + gib = kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT | GFP_DMA); if (!gib) { rc = -ENOMEM; goto out; @@ -3722,7 +3722,7 @@ int __init kvm_s390_gib_init(u8 nisc) gib_origin = virt_to_phys(gib); if (chsc_sgib(gib_origin)) { pr_err("Associating the GIB with the AIV facility failed\n"); - free_page((unsigned long)gib); + kfree(gib); gib = NULL; rc = -EIO; goto out_unreg_gal; @@ -3742,7 +3742,7 @@ int __init kvm_s390_gib_init(u8 nisc) out_unreg_gal: unregister_adapter_interrupt(&gib_alert_irq); out_free_gib: - free_page((unsigned long)gib); + kfree(gib); gib = NULL; out: return rc; -- 2.53.0