| Message ID | 20220517100219.15146-2-abhsahu@nvidia.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | vfio/pci: power management changes | expand |
Hi Abhishek,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on awilliam-vfio/next]
[also build test WARNING on v5.18-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/intel-lab-lkp/linux/commits/Abhishek-Sahu/vfio-pci-power-management-changes/20220517-180527
base: https://github.com/awilliam/linux-vfio.git next
config: x86_64-randconfig-s021-20220516 (https://download.01.org/0day-ci/archive/20220518/202205180721.m3Z4ar57-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.4-dirty
# https://github.com/intel-lab-lkp/linux/commit/2c439fb0dc917fb8bcf3cf432c8d73d51cfb16b0
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Abhishek-Sahu/vfio-pci-power-management-changes/20220517-180527
git checkout 2c439fb0dc917fb8bcf3cf432c8d73d51cfb16b0
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/vfio/pci/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
sparse warnings: (new ones prefixed by >>)
>> drivers/vfio/pci/vfio_pci_config.c:411:20: sparse: sparse: restricted pci_power_t degrades to integer
drivers/vfio/pci/vfio_pci_config.c:411:38: sparse: sparse: restricted pci_power_t degrades to integer
vim +411 drivers/vfio/pci/vfio_pci_config.c
397
398 /* Caller should hold memory_lock semaphore */
399 bool __vfio_pci_memory_enabled(struct vfio_pci_core_device *vdev)
400 {
401 struct pci_dev *pdev = vdev->pdev;
402 u16 cmd = le16_to_cpu(*(__le16 *)&vdev->vconfig[PCI_COMMAND]);
403
404 /*
405 * Memory region cannot be accessed if device power state is D3.
406 *
407 * SR-IOV VF memory enable is handled by the MSE bit in the
408 * PF SR-IOV capability, there's therefore no need to trigger
409 * faults based on the virtual value.
410 */
> 411 return pdev->current_state < PCI_D3hot &&
412 (pdev->no_command_memory || (cmd & PCI_COMMAND_MEMORY));
413 }
414
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c index 6e58b4bf7a60..d9077627117f 100644 --- a/drivers/vfio/pci/vfio_pci_config.c +++ b/drivers/vfio/pci/vfio_pci_config.c @@ -402,11 +402,14 @@ bool __vfio_pci_memory_enabled(struct vfio_pci_core_device *vdev) u16 cmd = le16_to_cpu(*(__le16 *)&vdev->vconfig[PCI_COMMAND]); /* + * Memory region cannot be accessed if device power state is D3. + * * SR-IOV VF memory enable is handled by the MSE bit in the * PF SR-IOV capability, there's therefore no need to trigger * faults based on the virtual value. */ - return pdev->no_command_memory || (cmd & PCI_COMMAND_MEMORY); + return pdev->current_state < PCI_D3hot && + (pdev->no_command_memory || (cmd & PCI_COMMAND_MEMORY)); } /* @@ -718,7 +721,7 @@ static int vfio_pm_config_write(struct vfio_pci_core_device *vdev, int pos, break; } - vfio_pci_set_power_state(vdev, state); + vfio_pci_lock_and_set_power_state(vdev, state); } return count; diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 05a3aa95ba52..b9f222ca48cf 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -255,6 +255,22 @@ int vfio_pci_set_power_state(struct vfio_pci_core_device *vdev, pci_power_t stat return ret; } +/* + * It takes all the required locks to protect the access of power related + * variables and then invokes vfio_pci_set_power_state(). + */ +void vfio_pci_lock_and_set_power_state(struct vfio_pci_core_device *vdev, + pci_power_t state) +{ + if (state >= PCI_D3hot) + vfio_pci_zap_and_down_write_memory_lock(vdev); + else + down_write(&vdev->memory_lock); + + vfio_pci_set_power_state(vdev, state); + up_write(&vdev->memory_lock); +} + int vfio_pci_core_enable(struct vfio_pci_core_device *vdev) { struct pci_dev *pdev = vdev->pdev; diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index 23c176d4b073..8f20056e0b8d 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -189,6 +189,8 @@ extern int vfio_pci_register_dev_region(struct vfio_pci_core_device *vdev, extern int vfio_pci_set_power_state(struct vfio_pci_core_device *vdev, pci_power_t state); +extern void vfio_pci_lock_and_set_power_state(struct vfio_pci_core_device *vdev, + pci_power_t state); extern bool __vfio_pci_memory_enabled(struct vfio_pci_core_device *vdev); extern void vfio_pci_zap_and_down_write_memory_lock(struct vfio_pci_core_device
According to [PCIe v5 5.3.1.4.1] for D3hot state "Configuration and Message requests are the only TLPs accepted by a Function in the D3Hot state. All other received Requests must be handled as Unsupported Requests, and all received Completions may optionally be handled as Unexpected Completions." Currently, if the vfio PCI device has been put into D3hot state and if user makes non-config related read/write request in D3hot state, these requests will be forwarded to the host and this access may cause issues on a few systems. This patch leverages the memory-disable support added in commit 'abafbc551fdd ("vfio-pci: Invalidate mmaps and block MMIO access on disabled memory")' to generate page fault on mmap access and return error for the direct read/write. If the device is D3hot state, then the error will be returned for MMIO access. The IO access generally does not make the system unresponsive so the IO access can still happen in D3hot state. The default value should be returned in this case without bringing down the complete system. Also, the power related structure fields need to be protected so we can use the same 'memory_lock' to protect these fields also. This protection is mainly needed when user changes the PCI power state by writing into PCI_PM_CTRL register. vfio_pci_lock_and_set_power_state() wrapper function will take the required locks and then it will invoke the vfio_pci_set_power_state(). Signed-off-by: Abhishek Sahu <abhsahu@nvidia.com> --- drivers/vfio/pci/vfio_pci_config.c | 7 +++++-- drivers/vfio/pci/vfio_pci_core.c | 16 ++++++++++++++++ include/linux/vfio_pci_core.h | 2 ++ 3 files changed, 23 insertions(+), 2 deletions(-)