ahci: warn about remapped NVMe devices (aecec8b6) · Commits · 戴 / test

Some Intel ahci implementations have a completely broken remapping mode where they hide one or more NVMe devices behind the bar of an AHCI device. Intel refuses to let the OS reprogram the BIOS to switch out of this mode at runtime, and so far we're not come up with another good way to undo the mess that the Chipset people created. So for now the only thing we can do is to alert users about this situation and switch to the faster and much saner so called "AHCI" mode insted of the RAID mode in the BIOS so that the BIOS does not hide the NVMe devices from us. The sitation is even worse as at least one vendor (thanks a lot Lenovo..) has started hardcoding their BIOS into the "RAID" mode even for laptops that don't use AHCI _at all_ and just have a single NVMe device. For now there is an unspported Linux-only BIOS that undoes this braindamage, but we'll have to see if things are getting better or worse from here. Based on an earlier patch from Dan Williams <dan.j.williams@intel.com>. Signed-off-by:

Christoph Hellwig <hch@lst.de> Signed-off-by:

Tejun Heo <tj@kernel.org>

drivers/ata/ahci.c

+39 −0

Original line number	Diff line number	Diff line
		@@ -46,6 +46,8 @@
		#include <scsi/scsi_host.h>
		#include <scsi/scsi_cmnd.h>
		#include <linux/libata.h>
		#include <linux/ahci-remap.h>
		#include <linux/io-64-nonatomic-lo-hi.h>
		#include "ahci.h"

		#define DRV_NAME "ahci"
		@@ -1400,6 +1402,40 @@ static irqreturn_t ahci_thunderx_irq_handler(int irq, void *dev_instance)
		}
		#endif

		static void ahci_remap_check(struct pci_dev *pdev, int bar,
		struct ahci_host_priv *hpriv)
		{
		int i, count = 0;
		u32 cap;

		/*
		* Check if this device might have remapped nvme devices.
		*/
		if (pdev->vendor != PCI_VENDOR_ID_INTEL \|\|
		pci_resource_len(pdev, bar) < SZ_512K \|\|
		bar != AHCI_PCI_BAR_STANDARD \|\|
		!(readl(hpriv->mmio + AHCI_VSCAP) & 1))
		return;

		cap = readq(hpriv->mmio + AHCI_REMAP_CAP);
		for (i = 0; i < AHCI_MAX_REMAP; i++) {
		if ((cap & (1 << i)) == 0)
		continue;
		if (readl(hpriv->mmio + ahci_remap_dcc(i))
		!= PCI_CLASS_STORAGE_EXPRESS)
		continue;

		/* We've found a remapped device */
		count++;
		}

		if (!count)
		return;

		dev_warn(&pdev->dev, "Found %d remapped NVMe devices.\n", count);
		dev_warn(&pdev->dev, "Switch your BIOS from RAID to AHCI mode to use them.\n");
		}

		static int ahci_get_irq_vector(struct ata_host *host, int port)
		{
		return pci_irq_vector(to_pci_dev(host->dev), port);
		@@ -1545,6 +1581,9 @@ static int ahci_init_one(struct pci_dev pdev, const struct pci_device_id ent)

		hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];

		/* detect remapped nvme devices */
		ahci_remap_check(pdev, ahci_pci_bar, hpriv);

		/* must set flag prior to save config in order to take effect */
		if (ahci_broken_devslp(pdev))
		hpriv->flags \|= AHCI_HFLAG_NO_DEVSLP;

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