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[98.234.52.230]) by smtp.gmail.com with ESMTPSA id c1sm39259301pfo.44.2020.01.04.14.51.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 04 Jan 2020 14:51:53 -0800 (PST) From: Deepa Dinamani To: bhelgaas@google.com Cc: mika.westerberg@linux.intel.com, alex.williamson@redhat.com, logang@deltatee.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] drivers: pci: Clear ACS state at kexec Date: Sat, 4 Jan 2020 14:51:49 -0800 Message-Id: <20200104225149.27342-1-deepa.kernel@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org ACS bits remain sticky through kexec reset. This is not really a problem for Linux because turning IOMMU on assumes ACS on. But, this becomes a problem if we kexec into something other than Linux and that does not turn ACS on always. Reset the ACS bits to default before kexec or device remove. Signed-off-by: Deepa Dinamani --- drivers/pci/pci-driver.c | 4 ++++ drivers/pci/pci.c | 39 +++++++++++++++++++++++++++------------ drivers/pci/pci.h | 1 + 3 files changed, 32 insertions(+), 12 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 0454ca0e4e3f..bd8d08e50b97 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -453,6 +453,8 @@ static int pci_device_remove(struct device *dev) /* Undo the runtime PM settings in local_pci_probe() */ pm_runtime_put_sync(dev); + /* Undo the PCI ACS settings in pci_init_capabilities() */ + pci_disable_acs(pci_dev); /* * If the device is still on, set the power state as "unknown", @@ -493,6 +495,8 @@ static void pci_device_shutdown(struct device *dev) */ if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot)) pci_clear_master(pci_dev); + if (kexec_in_progress) + pci_disable_acs(pci_dev); } #ifdef CONFIG_PM diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index da2e59daad6f..8254617cff03 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3261,15 +3261,23 @@ static void pci_disable_acs_redir(struct pci_dev *dev) pci_info(dev, "disabled ACS redirect\n"); } + +/* Standard PCI ACS capailities + * Source Validation | P2P Request Redirect | P2P Completion Redirect | Upstream Forwarding + */ +#define PCI_STD_ACS_CAP (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF) + /** - * pci_std_enable_acs - enable ACS on devices using standard ACS capabilities + * pci_std_enable_disable_acs - enable/disable ACS on devices using standard + * ACS capabilities * @dev: the PCI device */ -static void pci_std_enable_acs(struct pci_dev *dev) +static void pci_std_enable_disable_acs(struct pci_dev *dev, int enable) { int pos; u16 cap; u16 ctrl; + u16 val = 0; pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS); if (!pos) @@ -3278,19 +3286,26 @@ static void pci_std_enable_acs(struct pci_dev *dev) pci_read_config_word(dev, pos + PCI_ACS_CAP, &cap); pci_read_config_word(dev, pos + PCI_ACS_CTRL, &ctrl); - /* Source Validation */ - ctrl |= (cap & PCI_ACS_SV); + val = (cap & PCI_STD_ACS_CAP); - /* P2P Request Redirect */ - ctrl |= (cap & PCI_ACS_RR); + if (enable) + ctrl |= val; + else + ctrl &= ~val; - /* P2P Completion Redirect */ - ctrl |= (cap & PCI_ACS_CR); + pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl); +} - /* Upstream Forwarding */ - ctrl |= (cap & PCI_ACS_UF); +/** + * pci_disable_acs - enable ACS if hardware support it + * @dev: the PCI device + */ +void pci_disable_acs(struct pci_dev *dev) +{ + if (pci_acs_enable) + pci_std_enable_disable_acs(dev, 0); - pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl); + pci_disable_acs_redir(dev); } /** @@ -3305,7 +3320,7 @@ void pci_enable_acs(struct pci_dev *dev) if (!pci_dev_specific_enable_acs(dev)) goto disable_acs_redir; - pci_std_enable_acs(dev); + pci_std_enable_disable_acs(dev, 1); disable_acs_redir: /* diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 6394e7746fb5..480e4de46fa8 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -526,6 +526,7 @@ static inline resource_size_t pci_resource_alignment(struct pci_dev *dev, } void pci_enable_acs(struct pci_dev *dev); +void pci_disable_acs(struct pci_dev *dev); #ifdef CONFIG_PCI_QUIRKS int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags); int pci_dev_specific_enable_acs(struct pci_dev *dev);