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PCI/IOV: Adjust ->barsz[] when changing BAR size

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pci_rebar_set_size() adjusts BAR size for both normal and IOV BARs. The
struct pci_sriov keeps a cached copy of BAR size in ->barsz[] which is not
adjusted by pci_rebar_set_size() but by pci_iov_resource_set_size().
pci_iov_resource_set_size() is called also from
pci_resize_resource_set_size().

The current arrangement is problematic once BAR resize algorithm starts to
roll back changes properly in case of a failure. The normal resource
fitting algorithm rolls back resource size using the struct
pci_dev_resource easily but also calling pci_resize_resource_set_size() or
pci_iov_resource_set_size() to roll back BAR size would be an extra burden,
whereas combining ->barsz[] update with pci_rebar_set_size() naturally
rolls back it when restoring the old BAR size on a different layer of the
BAR resize operation.

Thus, rework pci_rebar_set_size() to also update ->barsz[].

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org> # AVA, AMD GPU
Link: https://patch.msgid.link/20251113162628.5946-3-ilpo.jarvinen@linux.intel.com
This commit is contained in:
Ilpo Järvinen 2025-11-13 18:26:19 +02:00 committed by Bjorn Helgaas
parent 91c4c89db4
commit 4687b3315a
4 changed files with 14 additions and 20 deletions
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15
drivers/pci/iov.c
View File

@ -158,8 +158,7 @@ resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
return dev->sriov->barsz[pci_resource_num_to_vf_bar(resno)];
}
void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
resource_size_t size)
void pci_iov_resource_set_size(struct pci_dev *dev, int resno, int size)
{
if (!pci_resource_is_iov(resno)) {
pci_warn(dev, "%s is not an IOV resource\n",
@ -167,7 +166,8 @@ void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
return;
}
dev->sriov->barsz[pci_resource_num_to_vf_bar(resno)] = size;
resno = pci_resource_num_to_vf_bar(resno);
dev->sriov->barsz[resno] = pci_rebar_size_to_bytes(size);
}
bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
@ -1340,7 +1340,6 @@ EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);
int pci_iov_vf_bar_set_size(struct pci_dev *dev, int resno, int size)
{
u32 sizes;
int ret;
if (!pci_resource_is_iov(resno))
return -EINVAL;
@ -1355,13 +1354,7 @@ int pci_iov_vf_bar_set_size(struct pci_dev *dev, int resno, int size)
if (!(sizes & BIT(size)))
return -EINVAL;
ret = pci_rebar_set_size(dev, resno, size);
if (ret)
return ret;
pci_iov_resource_set_size(dev, resno, pci_rebar_size_to_bytes(size));
return 0;
return pci_rebar_set_size(dev, resno, size);
}
EXPORT_SYMBOL_GPL(pci_iov_vf_bar_set_size);

4
drivers/pci/pci.c
View File

@ -3803,6 +3803,10 @@ int pci_rebar_set_size(struct pci_dev *pdev, int bar, int size)
ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
ctrl |= FIELD_PREP(PCI_REBAR_CTRL_BAR_SIZE, size);
pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);
if (pci_resource_is_iov(bar))
pci_iov_resource_set_size(pdev, bar, size);
return 0;
}

5
drivers/pci/pci.h
View File

@ -808,8 +808,7 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno);
resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno);
void pci_restore_iov_state(struct pci_dev *dev);
int pci_iov_bus_range(struct pci_bus *bus);
void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
resource_size_t size);
void pci_iov_resource_set_size(struct pci_dev *dev, int resno, int size);
bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev);
static inline u16 pci_iov_vf_rebar_cap(struct pci_dev *dev)
{
@ -851,7 +850,7 @@ static inline int pci_iov_bus_range(struct pci_bus *bus)
return 0;
}
static inline void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
resource_size_t size) { }
int size) { }
static inline bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
{
return false;

10
drivers/pci/setup-res.c
View File

@ -450,12 +450,10 @@ static void pci_resize_resource_set_size(struct pci_dev *dev, int resno,
resource_size_t res_size = pci_rebar_size_to_bytes(size);
struct resource *res = pci_resource_n(dev, resno);
if (!pci_resource_is_iov(resno)) {
resource_set_size(res, res_size);
} else {
resource_set_size(res, res_size * pci_sriov_get_totalvfs(dev));
pci_iov_resource_set_size(dev, resno, res_size);
}
if (pci_resource_is_iov(resno))
res_size *= pci_sriov_get_totalvfs(dev);
resource_set_size(res, res_size);
}
int pci_resize_resource(struct pci_dev *dev, int resno, int size)