From 8d6da6575ffec171161d36a06c015142b0049637 Mon Sep 17 00:00:00 2001 From: zhenwei pi Date: Sun, 10 Jan 2021 19:53:58 +0800 Subject: [PATCH] misc: pvpanic: introduce events device attribue Suggested by Paolo & Greg, add 'events' device attribute that can be used to limit which capabilities the driver uses. Finally, the pvpanic guest driver works by the limitation of both device capability and user setting. Signed-off-by: zhenwei pi Reviewed-by: Paolo Bonzini Link: https://lore.kernel.org/r/20210110115358.79100-3-pizhenwei@bytedance.com Signed-off-by: Greg Kroah-Hartman --- .../ABI/testing/sysfs-bus-pci-devices-pvpanic | 12 ++++++++ drivers/misc/pvpanic.c | 30 ++++++++++++++++++- 2 files changed, 41 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic b/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic index 79b7dc31cd55c..1936f73241557 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic +++ b/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic @@ -10,3 +10,15 @@ Description: Detailed bit definition refers to section from pvpanic device specification: https://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/specs/pvpanic.txt + +What: /sys/devices/pci0000:00/*/QEMU0001:00/events +Date: Jan 2021 +Contact: zhenwei pi +Description: + RW attribute. Set/get which features in-use. This attribute + is used to enable/disable feature(s) of pvpanic device. + Notice that this value should be a subset of capability. + + Format: %x. + + Also refer to pvpanic device specification. diff --git a/drivers/misc/pvpanic.c b/drivers/misc/pvpanic.c index 80cdfa8f951a9..b1e4922a7fda7 100644 --- a/drivers/misc/pvpanic.c +++ b/drivers/misc/pvpanic.c @@ -20,6 +20,7 @@ static void __iomem *base; static unsigned int capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED; +static unsigned int events; static ssize_t capability_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -28,8 +29,34 @@ static ssize_t capability_show(struct device *dev, } static DEVICE_ATTR_RO(capability); +static ssize_t events_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%x", events); +} + +static ssize_t events_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + unsigned int tmp; + int err; + + err = kstrtouint(buf, 16, &tmp); + if (err) + return err; + + if ((tmp & capability) != tmp) + return -EINVAL; + + events = tmp; + + return count; + +} +static DEVICE_ATTR_RW(events); + static struct attribute *pvpanic_dev_attrs[] = { &dev_attr_capability.attr, + &dev_attr_events.attr, NULL }; ATTRIBUTE_GROUPS(pvpanic_dev); @@ -41,7 +68,7 @@ MODULE_LICENSE("GPL"); static void pvpanic_send_event(unsigned int event) { - if (event & capability) + if (event & capability & events) iowrite8(event, base); } @@ -90,6 +117,7 @@ static int pvpanic_mmio_probe(struct platform_device *pdev) /* initlize capability by RDPT */ capability &= ioread8(base); + events = capability; if (capability) atomic_notifier_chain_register(&panic_notifier_list, -- 2.39.5