Patch "PCI/AER: Write AER Capability only when we control it" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    PCI/AER: Write AER Capability only when we control it

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-aer-write-aer-capability-only-when-we-control-it.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 940b28e989ee3668c245fa1ade17e5229152c4c1
Author: Sean V Kelley <sean.v.kelley@xxxxxxxxx>
Date:   Fri Nov 20 16:10:22 2020 -0800

    PCI/AER: Write AER Capability only when we control it
    
    [ Upstream commit 50cc18fcd3053fb46a09db5a39e6516e9560f765 ]
    
    If an OS has not been granted AER control via _OSC, it should not make
    changes to PCI_ERR_ROOT_COMMAND and PCI_ERR_ROOT_STATUS related registers.
    Per section 4.5.1 of the System Firmware Intermediary (SFI) _OSC and DPC
    Updates ECN [1], this bit also covers these aspects of the PCI Express
    Advanced Error Reporting. Based on the above and earlier discussion [2],
    make the following changes:
    
    Add a check for the native case (i.e., AER control via _OSC)
    
    Note that the previous "clear, reset, enable" order suggests that the reset
    might cause errors that we should ignore. After this commit, those errors
    (if any) will remain logged in the PCI_ERR_ROOT_STATUS register.
    
    [1] System Firmware Intermediary (SFI) _OSC and DPC Updates ECN, Feb 24,
        2020, affecting PCI Firmware Specification, Rev. 3.2
        https://members.pcisig.com/wg/PCI-SIG/document/14076
    [2] https://lore.kernel.org/linux-pci/20201020162820.GA370938@bjorn-Precision-5520/
    
    Link: https://lore.kernel.org/r/20201121001036.8560-2-sean.v.kelley@xxxxxxxxx
    Tested-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> # non-native/no RCEC
    Signed-off-by: Sean V Kelley <sean.v.kelley@xxxxxxxxx>
    Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index c40546eeecb3..61f78b20b0cf 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1366,23 +1366,26 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 	u32 reg32;
 	int rc;
 
-
-	/* Disable Root's interrupt in response to error messages */
-	pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
-	reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
-	pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+	if (pcie_aer_is_native(dev)) {
+		/* Disable Root's interrupt in response to error messages */
+		pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
+		reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
+		pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+	}
 
 	rc = pci_bus_error_reset(dev);
-	pci_info(dev, "Root Port link has been reset\n");
+	pci_info(dev, "Root Port link has been reset (%d)\n", rc);
 
-	/* Clear Root Error Status */
-	pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, &reg32);
-	pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, reg32);
+	if (pcie_aer_is_native(dev)) {
+		/* Clear Root Error Status */
+		pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, &reg32);
+		pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, reg32);
 
-	/* Enable Root Port's interrupt in response to error messages */
-	pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
-	reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
-	pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+		/* Enable Root Port's interrupt in response to error messages */
+		pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
+		reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
+		pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+	}
 
 	return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
 }