From nobody Sat Sep 26 11:01:15 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E560B390609; Wed, 2 Sep 2026 06:15:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329735; cv=none; b=tAujlfnNYWhqLali2/sfXvgeVZPnjNcJldg6oZ26pX9h9jrhszdWYZ2nrRFPlxGYTQgk9fpnXIF2AJ6WtFLmwwWu4sqaCP+Z5vaVnWdlZCPeyhoFBDxyyss9CjN1FfF4ZPmwPUYrF+IjxOuPWQddWo63wCXOMV9MvlvraAMoJms= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329735; c=relaxed/simple; bh=8U95+oHeCA/rmJkgUT/fvmjP+gRFb78XsoMfKDHsIVI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=OoDPb2UtwDnjI+cC93yHObrpewl47ysmr71lvgV4w+KPFFn4+byjd669L2ir1lbqIA3CN3bjyq07T3M9jsKCIZTct/qE/g3jg5I/kWD7NkV+0vYV+p+4z7te2WBoHV2vAQcN69wnyBj//dbZdX2stIZpnyGj9Pg3IPGkDePjg64= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RyCC6K3+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RyCC6K3+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B38201F00A3A; Wed, 2 Sep 2026 06:15:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788329733; bh=rZDmOJa3lKJg3q4J0vxXiCwo1usJZY0dSBwZL2xaIK4=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=RyCC6K3+yoBVj6HOL+jhCmJspI1rOOtMlmlJ09dU7HJTzqEQmvW2aI/S1sfTHPfj6 ZHYdLXxvZEV213yRt6hcyicUWOkk/fmtKZ2RbcigWIVDgqKvgU4dQNyaPa3tdhRynn UmyYgIsw6J0sWUvzPkXwjZYh+twK/i+vDC+6T4STp0EIiC0Lknuutak3P8VrbsKjOT 9jh7aG7AnlP2sL5unVXGeaY3Dzug0feoyhj1sILuc+230lbhU7aXqxUVJGiXrHlVt2 nsi5FDvTfJt+DSOgof/YYHzGjA6EsF0FFHUoTrVFeq7ELA2DJhEqGbMzj/f0c2ZSy4 nk9//iAEyiEjQ== From: "Mike Rapoport (Microsoft)" Date: Wed, 02 Sep 2026 09:15:13 +0300 Subject: [PATCH 1/4] KVM: s390: Replace get_zeroed_page() with kzalloc() for the STHYI buffer Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260902-s390-kvm-v1-1-3bc0986550b1@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 handle_sthyi() allocates the buffer that receives the STHYI response block before it is copied to the guest. 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@redh= at.com Assisted-by: copilot:claude-opus Signed-off-by: Mike Rapoport (Microsoft) --- arch/s390/kvm/s390/intercept.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/s390/kvm/s390/intercept.c b/arch/s390/kvm/s390/intercept.c index ca1205dfac8b0..aaf9828d1f44d 100644 --- a/arch/s390/kvm/s390/intercept.c +++ b/arch/s390/kvm/s390/intercept.c @@ -11,6 +11,7 @@ #include #include #include +#include =20 #include #include @@ -438,13 +439,13 @@ int handle_sthyi(struct kvm_vcpu *vcpu) if (!kvm_s390_pv_cpu_is_protected(vcpu) && (addr & ~PAGE_MASK)) return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); =20 - sctns =3D (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); + sctns =3D kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); if (!sctns) return -ENOMEM; =20 cc =3D sthyi_fill(sctns, &rc); if (cc < 0) { - free_page((unsigned long)sctns); + kfree(sctns); return cc; } out: @@ -454,13 +455,13 @@ int handle_sthyi(struct kvm_vcpu *vcpu) } else { r =3D write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE); if (r) { - free_page((unsigned long)sctns); + kfree(sctns); return kvm_s390_inject_prog_cond(vcpu, r); } } } =20 - free_page((unsigned long)sctns); + kfree(sctns); vcpu->run->s.regs.gprs[reg2 + 1] =3D rc; kvm_s390_set_psw_cc(vcpu, cc); return r; --=20 2.53.0 From nobody Sat Sep 26 11:01:15 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2094938E8DC; Wed, 2 Sep 2026 06:15:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329742; cv=none; b=jbdEI3n/6e2idQbUUTmmKCa657qNb0dwkeNcn2KySP912RMqI7tQJRP5UmAj4qXOCXzvW6VuJbYRxql6a/6BDJoGaQgQnpnX1Hr3lVrSYmQDIK1AMQAKkOx7S33lg7AK7jVmpTQve7pe7CfVmUWRgskyykgXKmC+lSvEVvamrFU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329742; c=relaxed/simple; bh=KjSvS6cVarz2EGcjO+qgUC/Z3Ug9TAUlDU9fkjFomJM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gTYhlirMuq/q7ouiOCcDnLPgrtLDuf+Uq9Sts2zFWNwilyg2+sp1Tqr0E1Zunsk+aJoBmB0wb4JliI7zruwiKj81nBSEd26b4OUoEyn32kKTu2IEmoiSzwxIg9bwn08b/4TvPBz5jpAm+0pZDge7u5YZTzKIqUEP5MKvpNBqN90= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WvNXHcrx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WvNXHcrx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 587011F000E9; Wed, 2 Sep 2026 06:15:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788329737; bh=YsA6hNpdDuoXhmxFeC3uv8uIXxR1ksQ/iBUtdB1feUs=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=WvNXHcrxV8JKaRtt3T+TgHowGmPOJ4H4MgCw7LvVDttuAHoV8YajbSc586+Rw1gFT 1fgWfos2HoEwwgGmf2fwT7rUv/cZnEG6lheWHkQhjlrHRPyeM6CgQ35aBMGDOlIDQb /fcMnjoLLunKuouuieMHEpD/HuxY9/fPUdnP1LS1tlXNxz4gZriv8nN3DIKHWLT+BK C9qIfJouDe3OtAGA5Rqgs8L3WfXmxVGyHhfOx0HskVeGN/LsdbVntcaw3cwgRNjaAs eydF7OqQZjyyls4A7K32MsYBafb4e24W6+SewzgGWol4DaaEcQIGEkf/29pCIx6ML/ Ts5YBGxnhGnGw== From: "Mike Rapoport (Microsoft)" Date: Wed, 02 Sep 2026 09:15:14 +0300 Subject: [PATCH 2/4] KVM: s390: Replace get_zeroed_page() with kzalloc() for the STSI buffer Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260902-s390-kvm-v1-2-3bc0986550b1@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 handle_stsi() allocates the buffer that receives the STSI response block before it is copied to the guest. 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. While on it, make the buffer a void pointer to get rid of the casts. Replace use of get_zeroed_page() with kzalloc() and free_page() with kfree(). Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redh= at.com Assisted-by: copilot:claude-opus Signed-off-by: Mike Rapoport (Microsoft) --- arch/s390/kvm/s390/priv.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/arch/s390/kvm/s390/priv.c b/arch/s390/kvm/s390/priv.c index b3cb2c2c3aa71..856939acf012f 100644 --- a/arch/s390/kvm/s390/priv.c +++ b/arch/s390/kvm/s390/priv.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -869,7 +870,7 @@ static int handle_stsi(struct kvm_vcpu *vcpu) int fc =3D (vcpu->run->s.regs.gprs[0] & 0xf0000000) >> 28; int sel1 =3D vcpu->run->s.regs.gprs[0] & 0xff; int sel2 =3D vcpu->run->s.regs.gprs[1] & 0xffff; - unsigned long mem =3D 0; + void *mem =3D NULL; u64 operand2; int rc =3D 0; u8 ar; @@ -911,19 +912,19 @@ static int handle_stsi(struct kvm_vcpu *vcpu) switch (fc) { case 1: /* same handling for 1 and 2 */ case 2: - mem =3D get_zeroed_page(GFP_KERNEL_ACCOUNT); + mem =3D kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); if (!mem) goto out_no_data; - if (stsi((void *) mem, fc, sel1, sel2)) + if (stsi(mem, fc, sel1, sel2)) goto out_no_data; break; case 3: if (sel1 !=3D 2 || sel2 !=3D 2) goto out_no_data; - mem =3D get_zeroed_page(GFP_KERNEL_ACCOUNT); + mem =3D kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); if (!mem) goto out_no_data; - handle_stsi_3_2_2(vcpu, (void *) mem); + handle_stsi_3_2_2(vcpu, mem); break; case 15: /* fc 15 is fully handled in userspace */ insert_stsi_usr_data(vcpu, operand2, ar, fc, sel1, sel2); @@ -931,10 +932,10 @@ static int handle_stsi(struct kvm_vcpu *vcpu) return -EREMOTE; } if (kvm_s390_pv_cpu_is_protected(vcpu)) { - memcpy(sida_addr(vcpu->arch.sie_block), (void *)mem, PAGE_SIZE); + memcpy(sida_addr(vcpu->arch.sie_block), mem, PAGE_SIZE); rc =3D 0; } else { - rc =3D write_guest(vcpu, operand2, ar, (void *)mem, PAGE_SIZE); + rc =3D write_guest(vcpu, operand2, ar, mem, PAGE_SIZE); } if (rc) { rc =3D kvm_s390_inject_prog_cond(vcpu, rc); @@ -945,14 +946,14 @@ static int handle_stsi(struct kvm_vcpu *vcpu) rc =3D -EREMOTE; } trace_kvm_s390_handle_stsi(vcpu, fc, sel1, sel2, operand2); - free_page(mem); + kfree(mem); kvm_s390_set_psw_cc(vcpu, 0); vcpu->run->s.regs.gprs[0] =3D 0; return rc; out_no_data: kvm_s390_set_psw_cc(vcpu, 3); out: - free_page(mem); + kfree(mem); return rc; } =20 --=20 2.53.0 From nobody Sat Sep 26 11:01:15 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 75E9D386C3D; Wed, 2 Sep 2026 06:15:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329743; cv=none; b=pN90J5kFb+XKd2bGrWD5SNpLGPFugPNJlCyJGEzXJG3Sgy6/6V22m2HsyomJmwUgPbV449JEDWwi8BUoZ6tQ5edvQrVbSRLjVX1LlxSXx65OikHJQThplTbnYnsd0PK5LflBK5dWyQfOVzrToG6JGiLr/7dGX/vkEBzGn1sd2Bw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329743; c=relaxed/simple; bh=3Kxvl3vX0xOruGJqXO47tS1ILmPa2NLsdEexPXqkiRw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=k4GwghO/Lmq8dmWmxinraCHGyrniZKLmXb2aXiV3sbHSiLv+0UKA0GsKXkCVEuq6RpDRdSMKwBu1da7Jndy50nrXuVXPFKov6uEKf8CPqWIVuL66a/jbQiKsMBJBCQ434vd6o9eU/DYlkL3Rhs6YFPrn9nbo12Y5CwioGjej6cA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G85a2JdO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="G85a2JdO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F17D11F00A3A; Wed, 2 Sep 2026 06:15:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788329741; bh=JMHG+THezrVqv+LxM1LlqqUzwwh90wkGAEXs+OQ+QKU=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=G85a2JdOCh9i7kPV4oxSIFO3tRpnuXjL1+Hkbcz/GdOjbU+cATqvnUEkvo+HovQFS mDAzWVrbtoC2INqMSDc5cVraa5h+T8JwuKw8CFCVCv4kC99pg5ZSdTINyqVGt7mO8T vpktFiYmdzQe6eB+Ea7sfDCe1iPmcTKYvXmQ/EvrslTcD3T5Y7o5ZdCJmAXOPR5nTz PAGU1hcL9SqAe6Fkit46TtmSyAZOG6CbPSDHIwih9DekxMjW2G+sf4bHSDG85j1cI8 MGqs2jB1aBYz995A+yEML7RoaZgubgy92NM7kGvNO9htDihdnaOyYpoNzZVlqfRlLq h3DYFXRms4igQ== From: "Mike Rapoport (Microsoft)" Date: Wed, 02 Sep 2026 09:15:15 +0300 Subject: [PATCH 3/4] KVM: s390: Replace get_zeroed_page() with kzalloc() for the GIB Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260902-s390-kvm-v1-3-3bc0986550b1@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 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@redh= at.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 =3D NULL; } =20 @@ -3703,7 +3703,7 @@ int __init kvm_s390_gib_init(u8 nisc) goto out; } =20 - gib =3D (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL_ACCOUNT | GFP_D= MA); + gib =3D kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT | GFP_DMA); if (!gib) { rc =3D -ENOMEM; goto out; @@ -3722,7 +3722,7 @@ int __init kvm_s390_gib_init(u8 nisc) gib_origin =3D 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 =3D NULL; rc =3D -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 =3D NULL; out: return rc; --=20 2.53.0 From nobody Sat Sep 26 11:01:15 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05F5639150B; Wed, 2 Sep 2026 06:15:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329748; cv=none; b=PUBsy3Hb+QMa/FgccHdJg2QlG1mxVhQYVmJovBfMJmj6O7bv+eT806b8xXGtuzxFOTqnBBxm/HMYZY/A/oVmdlAlL+RUI2h61cSwNzpeQ3ZVuOEyv688M7AGkrYmSVS7PDjWT6rY6x92684Ot3Sv9HEy51cWt8rLQZy2gSGZxMI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788329748; c=relaxed/simple; bh=eYs7PvvK7m/4Bc+5SPo3ABQ7DJyDZT859glz5SE+vWQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=uGOxyDe08EAWvE/ypL1NxwAOX1RiCgBI22lM8LEhSun+uf+b71zWaT1UiblOC24xMr5+LLVkQ10BR7ONizltHDBZvaWY86DOVumaPZghyRpBSHPLcZRcIu92E5rurR8aFACLIsApmPe3UBx/gccbq6rAx0GwLmE8qQIxzYfGBJs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LB8X6Imi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LB8X6Imi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 986D31F00A3F; Wed, 2 Sep 2026 06:15:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788329744; bh=C0109/Wqd8Wh+hWY6seDc3gIIuk1v7uuHz7s+qR/LBc=; h=From:Date:Subject:References:In-Reply-To:To:Cc; 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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable 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 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@redh= at.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 t= ype) goto out_err; =20 BUILD_BUG_ON(sizeof(struct sie_page2) !=3D 4096); - kvm->arch.sie_page2 =3D - (struct sie_page2 *) get_zeroed_page(GFP_KERNEL_ACCOUNT | GFP_DMA); + kvm->arch.sie_page2 =3D kzalloc_obj(*kvm->arch.sie_page2, + GFP_KERNEL_ACCOUNT | GFP_DMA); if (!kvm->arch.sie_page2) goto out_err; =20 @@ -3369,7 +3369,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long t= ype) =20 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); =20 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_v= cpu *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 =3D 0; } =20 int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu) { - void *cbrlo_page =3D (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); + void *cbrlo_page =3D kzalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT); =20 if (!cbrlo_page) return -ENOMEM; --=20 2.53.0