From 34e651ff66f0966a59dacefaab1c84607fd33b2f Mon Sep 17 00:00:00 2001 From: Niklas Schnelle Date: Wed, 18 Mar 2020 13:53:16 +0100 Subject: [PATCH 01/12] s390/pci: Improve handling of unset UID When UID checking is enabled a UID value of 0 is invalid and can not be set by the user. On z/VM it is however used to indicate an unset UID. Until now, this lead to the behavior that one PCI function could be attached with UID 0 after which z/VM would prohibit further attachment. Now if the user then turns off UID checking in z/VM the user could seemingly attach additional PCI functions that would however not show up in Linux as that would not be informed of the change in UID checking mode. This is unexpected and confusing and lead to bug reports against Linux. Instead now, if we encounter an unset UID value of 0 treat it as indicating that UID checking was turned off, switch to automatic domain allocation, and warn the user of the possible misconfiguration. Signed-off-by: Niklas Schnelle Reviewed-by: Peter Oberparleiter Signed-off-by: Vasily Gorbik --- arch/s390/include/asm/pci.h | 3 +++ arch/s390/pci/pci.c | 8 ++++++++ arch/s390/pci/pci_clp.c | 2 +- 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h index 7850e8c8c79a..abce7aa6c8cb 100644 --- a/arch/s390/include/asm/pci.h +++ b/arch/s390/include/asm/pci.h @@ -190,6 +190,9 @@ int clp_enable_fh(struct zpci_dev *, u8); int clp_disable_fh(struct zpci_dev *); int clp_get_state(u32 fid, enum zpci_state *state); +/* UID */ +void update_uid_checking(bool new); + /* IOMMU Interface */ int zpci_init_iommu(struct zpci_dev *zdev); void zpci_destroy_iommu(struct zpci_dev *zdev); diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 0af46683dd66..c0f80e896d7b 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -662,6 +662,13 @@ static int zpci_alloc_domain(struct zpci_dev *zdev) if (zpci_unique_uid) { zdev->domain = (u16) zdev->uid; + if (zdev->domain == 0) { + pr_warn("UID checking is active but no UID is set for PCI function %08x, so automatic domain allocation is used instead\n", + zdev->fid); + update_uid_checking(false); + goto auto_allocate; + } + if (test_bit(zdev->domain, zpci_domain)) { spin_unlock(&zpci_domain_lock); pr_err("Adding PCI function %08x failed because domain %04x is already assigned\n", @@ -673,6 +680,7 @@ static int zpci_alloc_domain(struct zpci_dev *zdev) spin_unlock(&zpci_domain_lock); return 0; } +auto_allocate: /* * We can always auto allocate domains below ZPCI_NR_DEVICES. * There is either a free domain or we have reached the maximum in diff --git a/arch/s390/pci/pci_clp.c b/arch/s390/pci/pci_clp.c index 281e0dd4c614..cfc9ae9df85d 100644 --- a/arch/s390/pci/pci_clp.c +++ b/arch/s390/pci/pci_clp.c @@ -24,7 +24,7 @@ bool zpci_unique_uid; -static void update_uid_checking(bool new) +void update_uid_checking(bool new) { if (zpci_unique_uid != new) zpci_dbg(1, "uid checking:%d\n", new); -- 2.17.1