When a zPCI function is disabled and re-enabled, the firmware implicitly disables function measurement while the kernel still believes it is enabled, leading to a disconnect between the user-visible state and the actual device state. Make statistics_on represent the requested state instead. Introduce the functions zpci_fmb_request_on() and off(), which call zpci_fmb_enable() or disable() to perform the actual firmware change. This decouples the enablement or disablement from managing the user's desired state. Preserve the state in pcibios_enable_device(), pcibios_disable_device(), and zpci_reenable_device(), so measurement is restored automatically after a re-enable. New devices start with measurement on by default, unchanged from before. Signed-off-by: Omar Elghoul --- arch/s390/include/asm/pci.h | 8 +++-- arch/s390/pci/pci.c | 63 ++++++++++++++++++++++++++++++------- arch/s390/pci/pci_debug.c | 4 +-- 3 files changed, 58 insertions(+), 17 deletions(-) diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h index f4fea1c34746..dd7a17955362 100644 --- a/arch/s390/include/asm/pci.h +++ b/arch/s390/include/asm/pci.h @@ -208,7 +208,7 @@ struct zpci_dev { struct zpci_fmb *fmb; u16 fmb_update; /* update interval */ u16 fmb_length; - bool statistics_on; + bool statistics_on; /* desired FMB enablement */ u8 version; enum pci_bus_speed max_bus_speed; @@ -350,8 +350,10 @@ int zpci_create_parent_msi_domain(struct zpci_bus *zbus); void zpci_remove_parent_msi_domain(struct zpci_bus *zbus); /* FMB */ -int zpci_fmb_enable_device(struct zpci_dev *); -int zpci_fmb_disable_device(struct zpci_dev *); +int zpci_fmb_request_on(struct zpci_dev *zdev); +int zpci_fmb_request_off(struct zpci_dev *zdev); +int zpci_fmb_enable(struct zpci_dev *zdev); +int zpci_fmb_disable(struct zpci_dev *zdev); /* Debug */ int zpci_debug_init(void); diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 2a7e1ca0fa12..98a4e938865a 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -165,7 +165,37 @@ int zpci_unregister_ioat(struct zpci_dev *zdev, u8 dmaas) } /* Modify PCI: Set PCI function measurement parameters */ -int zpci_fmb_enable_device(struct zpci_dev *zdev) +int zpci_fmb_request_on(struct zpci_dev *zdev) +{ + lockdep_assert_held(&zdev->fmb_lock); + + if (zdev->statistics_on && zdev->fmb) + return -EINVAL; + + /* + * Record the user's intent first. If the enable fails, the flag stays set + * so we can retry enabling the FMB upon the next device (re-)enable. The + * consumer can detect that a measurement sample was never written if the + * timestamp is still zero, or if the FMB pointer is null. + */ + zdev->statistics_on = true; + return zpci_fmb_enable(zdev); +} + +/* Modify PCI: Disable PCI function measurement */ +int zpci_fmb_request_off(struct zpci_dev *zdev) +{ + lockdep_assert_held(&zdev->fmb_lock); + + if (!zdev->statistics_on) + return -EINVAL; + + zdev->statistics_on = false; + return zpci_fmb_disable(zdev); +} +EXPORT_SYMBOL_GPL(zpci_fmb_request_off); + +int zpci_fmb_enable(struct zpci_dev *zdev) { u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_SET_MEASURE); struct zpci_iommu_ctrs *ctrs; @@ -175,7 +205,7 @@ int zpci_fmb_enable_device(struct zpci_dev *zdev) lockdep_assert_held(&zdev->fmb_lock); - if (zdev->statistics_on || sizeof(*zdev->fmb) < zdev->fmb_length) + if (sizeof(*zdev->fmb) < zdev->fmb_length) return -EINVAL; if (!zdev->fmb) { @@ -206,12 +236,11 @@ int zpci_fmb_enable_device(struct zpci_dev *zdev) if (cc) return -EIO; - zdev->statistics_on = true; return 0; } +EXPORT_SYMBOL_GPL(zpci_fmb_enable); -/* Modify PCI: Disable PCI function measurement */ -int zpci_fmb_disable_device(struct zpci_dev *zdev) +int zpci_fmb_disable(struct zpci_dev *zdev) { u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_SET_MEASURE); struct zpci_fib fib = {0}; @@ -219,9 +248,6 @@ int zpci_fmb_disable_device(struct zpci_dev *zdev) lockdep_assert_held(&zdev->fmb_lock); - if (!zdev->statistics_on) - return -EINVAL; - fib.gd = zdev->gisa; /* Function measurement is disabled if fmb address is zero */ @@ -231,7 +257,6 @@ int zpci_fmb_disable_device(struct zpci_dev *zdev) if (cc) return -EIO; - zdev->statistics_on = false; return 0; } @@ -647,7 +672,8 @@ int pcibios_enable_device(struct pci_dev *pdev, int mask) zpci_debug_init_device(zdev, dev_name(&pdev->dev)); mutex_lock(&zdev->fmb_lock); - zpci_fmb_enable_device(zdev); + if (zdev->statistics_on) + zpci_fmb_enable(zdev); mutex_unlock(&zdev->fmb_lock); return pci_enable_resources(pdev, mask); @@ -658,7 +684,8 @@ void pcibios_disable_device(struct pci_dev *pdev) struct zpci_dev *zdev = to_zpci(pdev); mutex_lock(&zdev->fmb_lock); - zpci_fmb_disable_device(zdev); + if (zdev->statistics_on) + zpci_fmb_disable(zdev); mutex_unlock(&zdev->fmb_lock); zpci_debug_exit_device(zdev); } @@ -740,8 +767,14 @@ int zpci_reenable_device(struct zpci_dev *zdev) } rc = zpci_iommu_register_ioat(zdev, &status); - if (rc) + if (rc) { zpci_disable_device(zdev); + return rc; + } + + guard(mutex)(&zdev->fmb_lock); + if (zdev->statistics_on) + zpci_fmb_enable(zdev); return rc; } @@ -850,6 +883,12 @@ struct zpci_dev *zpci_create_device(u32 fid, u32 fh, enum zpci_state state) goto error; zdev->state = state; + /* + * Measurement is on by default for new functions, this will be honored + * by pcibios_enable_device(). + */ + zdev->statistics_on = true; + mutex_init(&zdev->state_lock); mutex_init(&zdev->fmb_lock); mutex_init(&zdev->kzdev_lock); diff --git a/arch/s390/pci/pci_debug.c b/arch/s390/pci/pci_debug.c index 419c6a9200a2..e479763858cd 100644 --- a/arch/s390/pci/pci_debug.c +++ b/arch/s390/pci/pci_debug.c @@ -156,10 +156,10 @@ static ssize_t pci_perf_seq_write(struct file *file, const char __user *ubuf, mutex_lock(&zdev->fmb_lock); switch (val) { case 0: - rc = zpci_fmb_disable_device(zdev); + rc = zpci_fmb_request_off(zdev); break; case 1: - rc = zpci_fmb_enable_device(zdev); + rc = zpci_fmb_request_on(zdev); break; } mutex_unlock(&zdev->fmb_lock); -- 2.56.0