| Message ID | 20220425092615.10133-2-abhsahu@nvidia.com |
|---|---|
| State | New |
| 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 v5.18-rc4]
[also build test WARNING on next-20220422]
[cannot apply to awilliam-vfio/next]
[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/20220425-173224
base: af2d861d4cd2a4da5137f795ee3509e6f944a25b
config: x86_64-rhel-8.3-kselftests (https://download.01.org/0day-ci/archive/20220426/202204260928.TsUAxMD3-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/1d48b86a17606c483f200c1734085ab415dbfc3c
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/20220425-173224
git checkout 1d48b86a17606c483f200c1734085ab415dbfc3c
# 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:703:13: sparse: sparse: restricted pci_power_t degrades to integer
drivers/vfio/pci/vfio_pci_config.c:703:22: sparse: sparse: restricted pci_power_t degrades to integer
vim +703 drivers/vfio/pci/vfio_pci_config.c
694
695 /*
696 * It takes all the required locks to protect the access of power related
697 * variables and then invokes vfio_pci_set_power_state().
698 */
699 static void
700 vfio_lock_and_set_power_state(struct vfio_pci_core_device *vdev,
701 pci_power_t state)
702 {
> 703 if (state >= PCI_D3hot)
704 vfio_pci_zap_and_down_write_memory_lock(vdev);
705 else
706 down_write(&vdev->memory_lock);
707
708 vfio_pci_set_power_state(vdev, state);
709 up_write(&vdev->memory_lock);
710 }
711
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c index 6e58b4bf7a60..dd557edae6e1 100644 --- a/drivers/vfio/pci/vfio_pci_config.c +++ b/drivers/vfio/pci/vfio_pci_config.c @@ -692,6 +692,23 @@ static int __init init_pci_cap_basic_perm(struct perm_bits *perm) return 0; } +/* + * It takes all the required locks to protect the access of power related + * variables and then invokes vfio_pci_set_power_state(). + */ +static void +vfio_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); +} + static int vfio_pm_config_write(struct vfio_pci_core_device *vdev, int pos, int count, struct perm_bits *perm, int offset, __le32 val) @@ -718,7 +735,7 @@ static int vfio_pm_config_write(struct vfio_pci_core_device *vdev, int pos, break; } - vfio_pci_set_power_state(vdev, state); + vfio_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 06b6f3594a13..f3dfb033e1c4 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -230,6 +230,8 @@ int vfio_pci_set_power_state(struct vfio_pci_core_device *vdev, pci_power_t stat ret = pci_set_power_state(pdev, state); if (!ret) { + vdev->power_state_d3 = (pdev->current_state >= PCI_D3hot); + /* D3 might be unsupported via quirk, skip unless in D3 */ if (needs_save && pdev->current_state >= PCI_D3hot) { /* @@ -1398,7 +1400,7 @@ static vm_fault_t vfio_pci_mmap_fault(struct vm_fault *vmf) mutex_lock(&vdev->vma_lock); down_read(&vdev->memory_lock); - if (!__vfio_pci_memory_enabled(vdev)) { + if (!__vfio_pci_memory_enabled(vdev) || vdev->power_state_d3) { ret = VM_FAULT_SIGBUS; goto up_out; } diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c index 82ac1569deb0..fac6bb40a4ce 100644 --- a/drivers/vfio/pci/vfio_pci_rdwr.c +++ b/drivers/vfio/pci/vfio_pci_rdwr.c @@ -43,7 +43,8 @@ static int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev, \ { \ if (test_mem) { \ down_read(&vdev->memory_lock); \ - if (!__vfio_pci_memory_enabled(vdev)) { \ + if (!__vfio_pci_memory_enabled(vdev) || \ + vdev->power_state_d3) { \ up_read(&vdev->memory_lock); \ return -EIO; \ } \ @@ -70,7 +71,8 @@ static int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev, \ { \ if (test_mem) { \ down_read(&vdev->memory_lock); \ - if (!__vfio_pci_memory_enabled(vdev)) { \ + if (!__vfio_pci_memory_enabled(vdev) || \ + vdev->power_state_d3) { \ up_read(&vdev->memory_lock); \ return -EIO; \ } \ diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index 48f2dd3c568c..505b2a74a479 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -124,6 +124,7 @@ struct vfio_pci_core_device { bool needs_reset; bool nointx; bool needs_pm_restore; + bool power_state_d3; struct pci_saved_state *pci_saved_state; struct pci_saved_state *pm_save; int ioeventfds_nr;
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_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 | 19 ++++++++++++++++++- drivers/vfio/pci/vfio_pci_core.c | 4 +++- drivers/vfio/pci/vfio_pci_rdwr.c | 6 ++++-- include/linux/vfio_pci_core.h | 1 + 4 files changed, 26 insertions(+), 4 deletions(-)