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(p200300cbc72bb500b53e6e32140827ac.dip0.t-ipconnect.de. [2003:cb:c72b:b500:b53e:6e32:1408:27ac]) by smtp.gmail.com with ESMTPSA id o5-20020a05600c510500b0040c1d2c6331sm41915101wms.32.2023.12.18.03.41.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Dec 2023 03:41:09 -0800 (PST) Message-ID: <35f54983-4209-40bd-aad0-f34c97f4a8b1@redhat.com> Date: Mon, 18 Dec 2023 12:41:08 +0100 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] virtio: Add support for no-reset virtio PCI PM Content-Language: en-US To: David Stevens Cc: "Michael S . Tsirkin" , Jason Wang , virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20231208070754.3132339-1-stevensd@chromium.org> <9fb51bfc-576a-4c7b-92c2-c161e7f08ae7@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 15.12.23 02:00, David Stevens wrote: > On Thu, Dec 14, 2023 at 6:47 PM David Hildenbrand wrote: >> >> On 08.12.23 08:07, David Stevens wrote: >>> If a virtio_pci_device supports native PCI power management and has the >>> No_Soft_Reset bit set, then skip resetting and reinitializing the device >>> when suspending and restoring the device. This allows system-wide low >>> power states like s2idle to be used in systems with stateful virtio >>> devices that can't simply be re-initialized (e.g. virtio-fs). >>> >>> Signed-off-by: David Stevens >>> --- >>> v1 -> v2: >>> - Check the No_Soft_Reset bit >>> >>> drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++- >>> 1 file changed, 33 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c >>> index c2524a7207cf..3a95ecaf12dc 100644 >>> --- a/drivers/virtio/virtio_pci_common.c >>> +++ b/drivers/virtio/virtio_pci_common.c >>> @@ -492,8 +492,40 @@ static int virtio_pci_restore(struct device *dev) >>> return virtio_device_restore(&vp_dev->vdev); >>> } >>> >>> +static bool vp_supports_pm_no_reset(struct device *dev) >>> +{ >>> + struct pci_dev *pci_dev = to_pci_dev(dev); >>> + u16 pmcsr; >>> + >>> + if (!pci_dev->pm_cap) >>> + return false; >>> + >>> + pci_read_config_word(pci_dev, pci_dev->pm_cap + PCI_PM_CTRL, &pmcsr); >>> + if (PCI_POSSIBLE_ERROR(pmcsr)) { >>> + dev_err(dev, "Unable to query pmcsr"); >>> + return false; >>> + } >>> + >>> + return pmcsr & PCI_PM_CTRL_NO_SOFT_RESET; >>> +} >>> + >>> +static int virtio_pci_suspend(struct device *dev) >>> +{ >>> + return vp_supports_pm_no_reset(dev) ? 0 : virtio_pci_freeze(dev); >>> +} >>> + >>> +static int virtio_pci_resume(struct device *dev) >>> +{ >>> + return vp_supports_pm_no_reset(dev) ? 0 : virtio_pci_restore(dev); >>> +} >>> + >>> static const struct dev_pm_ops virtio_pci_pm_ops = { >>> - SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore) >>> + .suspend = virtio_pci_suspend, >>> + .resume = virtio_pci_resume, >>> + .freeze = virtio_pci_freeze, >>> + .thaw = virtio_pci_restore, >>> + .poweroff = virtio_pci_freeze, >>> + .restore = virtio_pci_restore, >>> }; >>> #endif >>> >> >> Am I correct with my assumption that this will make s2idle work with virtio-mem-pci as well? >> >> Right now, all suspending is disabled, but really only s4/hibernate is problematic. >> >> [root@vm-0 ~]# echo "s2idle" > /sys/power/mem_sleep >> [root@vm-0 ~]# echo "mem" > /sys/power/state >> [ 101.822991] PM: suspend entry (s2idle) >> [ 101.828978] Filesystems sync: 0.004 seconds >> [ 101.831618] Freezing user space processes >> [ 101.834569] Freezing user space processes completed (elapsed 0.001 seconds) >> [ 101.836915] OOM killer disabled. >> [ 101.838072] Freezing remaining freezable tasks >> [ 101.841054] Freezing remaining freezable tasks completed (elapsed 0.001 seconds) >> [ 101.843538] printk: Suspending console(s) (use no_console_suspend to debug) >> [ 101.957676] virtio_mem virtio0: save/restore not supported. >> [ 101.957683] virtio-pci 0000:00:02.0: PM: pci_pm_suspend(): virtio_pci_freeze+0x0/0x50 returns -1 >> [ 101.957702] virtio-pci 0000:00:02.0: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x170 returns -1 >> [ 101.957718] virtio-pci 0000:00:02.0: PM: failed to suspend async: error -1 > > QEMU's virtio-pci devices don't advertise no_soft_reset, so this patch > won't affect vanilla QEMU. But if you add PCI_PM_CTRL_NO_SOFT_RESET to > the capability, then it should work. I'm working with crosvm, which > doesn't have virtio-mem implemented, but this patch makes virtio-fs > work with no extra kernel changes. Thanks for the explanation, makes sense to me. -- Cheers, David / dhildenb