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Mon, 24 Aug 2026 14:25:59 +0000 (GMT) Received: from [9.61.252.179] (unknown [9.61.252.179]) by smtpav06.dal12v.mail.ibm.com (Postfix) with ESMTP; Mon, 24 Aug 2026 14:25:59 +0000 (GMT) Message-ID: Date: Mon, 24 Aug 2026 10:25:59 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] KVM: s390: Fix dirty marking in adapter_indicators_set*() To: Matthew Rosato , Claudio Imbrenda , linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@kernel.org, seiden@linux.ibm.com, nrb@linux.ibm.com, schlameuss@linux.ibm.com, gra@linux.ibm.com References: <20260814163355.227191-1-imbrenda@linux.ibm.com> <20260814163355.227191-2-imbrenda@linux.ibm.com> Content-Language: en-US From: Douglas Freimuth In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=TfimcxQh c=1 sm=1 tr=0 ts=6a8c547a cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=j0IwUgC9Fpla6kIixDQA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwODI0MDExOCBTYWx0ZWRfX9vtjDv0Oe9vI Ny75ZnvmFb7E03BLv1WZt6RcxqDa4br+2i6hky5UXGixEnVPc41rhXd41fRM0L7Ecma1JvGFKak ms50ZZpacnJzwKr4FH1+IIhtrcTaPHY= X-Proofpoint-GUID: HdNg7eQiWzbG0VV-7xcwwOJ6zw6H_UVJ X-Proofpoint-ORIG-GUID: HdNg7eQiWzbG0VV-7xcwwOJ6zw6H_UVJ X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI0MDExOCBTYWx0ZWRfX6ux7X9mEopa5 P2zKxJkfUpX6VC3J9vy2sp8Awpo2MchUKK3fVwC2TIypkQZiXMvsMbBEzzfBjaixUSuEmqB5WH9 VSCCdVV7+lulLEYLS8ePh8LxZoFxOEzC1Q6YIiaZHgZT1q4rJJtvMh144b/zOQopQvrGsqHDNtS vFvFkASGRcj4LmExHhvT77UQGvI4GhyEEit1y8tC2FDc0Kc8v6/kx3g/7b3KCay15Lpq9oQXqsP 8vCiwIkMU4qAC4yW3szKb7NEjRXa+XfA/3lIRbp67dFoaayR8MF5PUKOeldLKrw7huWD8T6lvk7 M0X604qBwYV1inSSWe//8NwUsJdRnUEkuX7Y/ySj5gFZdnwUKe4pt+BeAt+aHwGbJaeBlO+ZW2X scve20clYerPzUIpUUHSqgWhybV+nAdgsRdRC7aVDXN9jKfms9NCfQoNuKbV5zeew5bfLnZS9Dm FUFAAw44y8+jonspYNw== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-24_04,2026-08-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 spamscore=0 bulkscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 phishscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608240118 On 8/18/26 4:43 PM, Matthew Rosato wrote: > On 8/14/26 12:33 PM, Claudio Imbrenda wrote: >> When the indicator and/or summary bits are set in the guest, the >> accessed page was only marked dirty in KVM if the access was performed >> using the slow path; accesses through the new kvm_arch_set_irq_inatomic >> fast inject path would not mark the page as dirty. >> >> Fix by adding/moving the missing calls to mark_page_dirty(). Note that >> for the inatomic path set_page_dirty{,_lock}() is not needed as the >> page stays pinned; the unpin path correctly marks it as dirty. >> >> Opportunistically reorder the local variables to be in reverse >> Christmas tree order and refactor to use guard(). >> >> Fixes: 1e95e3bc6b05 ("KVM: s390: Enable adapter_indicators_set to use mapped pages") >> Signed-off-by: Claudio Imbrenda > > The code itself looks good to me: > > Reviewed-by: Matthew Rosato > > Doug, can you please test (w/ lockdep enabled)? > > Thanks, > Matt > I did some testing (not exhaustive) with blkpvt and stressed with stress-ng to force paging and I didn't observe any lockdep messages. >> --- >> arch/s390/kvm/interrupt.c | 40 ++++++++++++++++++++------------------- >> 1 file changed, 21 insertions(+), 19 deletions(-) >> >> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c >> index da740a378a8c..fc4d1f8193d9 100644 >> --- a/arch/s390/kvm/interrupt.c >> +++ b/arch/s390/kvm/interrupt.c >> @@ -2984,12 +2984,14 @@ static int adapter_indicators_set(struct kvm *kvm, >> struct s390_io_adapter *adapter, >> struct kvm_s390_adapter_int *adapter_int) >> { >> - unsigned long bit; >> - int summary_set, idx; >> struct s390_map_info *ind_info, *summary_info; >> - void *map; >> struct page *ind_page, *summary_page; >> unsigned long flags; >> + unsigned long bit; >> + int summary_set; >> + void *map; >> + >> + guard(srcu)(&kvm->srcu); >> >> ind_page = NULL; >> >> @@ -3000,14 +3002,11 @@ static int adapter_indicators_set(struct kvm *kvm, >> ind_page = pin_map_page(kvm, adapter_int->ind_addr, 0); >> if (!ind_page) >> return -1; >> - idx = srcu_read_lock(&kvm->srcu); >> map = page_address(ind_page); >> bit = get_ind_bit(adapter_int->ind_addr, >> adapter_int->ind_offset, adapter->swap); >> set_bit(bit, map); >> - mark_page_dirty(kvm, adapter_int->ind_gaddr >> PAGE_SHIFT); >> set_page_dirty_lock(ind_page); >> - srcu_read_unlock(&kvm->srcu, idx); >> unpin_user_page(ind_page); >> } else { >> map = page_address(ind_info->page); >> @@ -3015,6 +3014,7 @@ static int adapter_indicators_set(struct kvm *kvm, >> set_bit(bit, map); >> spin_unlock_irqrestore(&adapter->maps_lock, flags); >> } >> + mark_page_dirty(kvm, gpa_to_gfn(adapter_int->ind_gaddr)); >> >> spin_lock_irqsave(&adapter->maps_lock, flags); >> summary_info = get_map_info(adapter, adapter_int->summary_addr); >> @@ -3023,14 +3023,11 @@ static int adapter_indicators_set(struct kvm *kvm, >> summary_page = pin_map_page(kvm, adapter_int->summary_addr, 0); >> if (!summary_page) >> return -1; >> - idx = srcu_read_lock(&kvm->srcu); >> map = page_address(summary_page); >> bit = get_ind_bit(adapter_int->summary_addr, >> adapter_int->summary_offset, adapter->swap); >> summary_set = test_and_set_bit(bit, map); >> - mark_page_dirty(kvm, adapter_int->summary_gaddr >> PAGE_SHIFT); >> set_page_dirty_lock(summary_page); >> - srcu_read_unlock(&kvm->srcu, idx); >> unpin_user_page(summary_page); >> } else { >> map = page_address(summary_info->page); >> @@ -3039,6 +3036,7 @@ static int adapter_indicators_set(struct kvm *kvm, >> summary_set = test_and_set_bit(bit, map); >> spin_unlock_irqrestore(&adapter->maps_lock, flags); >> } >> + mark_page_dirty(kvm, gpa_to_gfn(adapter_int->summary_gaddr)); >> >> return summary_set ? 0 : 1; >> } >> @@ -3048,26 +3046,29 @@ static int adapter_indicators_set_fast(struct kvm *kvm, >> struct kvm_s390_adapter_int *adapter_int, >> int setbit) >> { >> + struct s390_map_info *ind_info, *summary_info; >> unsigned long bit; >> int summary_set; >> - struct s390_map_info *ind_info, *summary_info; >> void *map; >> >> - spin_lock(&adapter->maps_lock); >> + guard(srcu)(&kvm->srcu); >> + guard(spinlock)(&adapter->maps_lock); >> + >> ind_info = get_map_info(adapter, adapter_int->ind_addr); >> - if (!ind_info) { >> - spin_unlock(&adapter->maps_lock); >> + if (!ind_info) >> return -EWOULDBLOCK; >> - } >> + >> map = page_address(ind_info->page); >> bit = get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->swap); >> - if (setbit) >> + if (setbit) { >> set_bit(bit, map); >> + mark_page_dirty(kvm, gpa_to_gfn(adapter_int->ind_gaddr)); >> + } >> + >> summary_info = get_map_info(adapter, adapter_int->summary_addr); >> - if (!summary_info) { >> - spin_unlock(&adapter->maps_lock); >> + if (!summary_info) >> return -EWOULDBLOCK; >> - } >> + >> map = page_address(summary_info->page); >> bit = get_ind_bit(summary_info->addr, adapter_int->summary_offset, >> adapter->swap); >> @@ -3077,7 +3078,8 @@ static int adapter_indicators_set_fast(struct kvm *kvm, >> summary_set = test_and_set_bit(bit, map); >> else >> summary_set = test_and_clear_bit(bit, map); >> - spin_unlock(&adapter->maps_lock); >> + mark_page_dirty(kvm, gpa_to_gfn(adapter_int->summary_gaddr)); >> + >> return summary_set ? 0 : 1; >> } >> >