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Message-ID: <d79a7a63-af36-9852-bc65-876bb8a8c842@linux.intel.com>
Date: Wed, 26 Mar 2025 16:58:14 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Michał Winiarski <michal.winiarski@...el.com>
cc: linux-pci@...r.kernel.org, intel-xe@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org, LKML <linux-kernel@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Christian König <christian.koenig@....com>,
Krzysztof Wilczyński <kw@...ux.com>,
Rodrigo Vivi <rodrigo.vivi@...el.com>,
Michal Wajdeczko <michal.wajdeczko@...el.com>,
Lucas De Marchi <lucas.demarchi@...el.com>,
Thomas Hellström <thomas.hellstrom@...ux.intel.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
Simona Vetter <simona@...ll.ch>, Matt Roper <matthew.d.roper@...el.com>
Subject: Re: [PATCH v6 3/6] PCI: Allow IOV resources to be resized in
pci_resize_resource()
On Thu, 20 Mar 2025, Michał Winiarski wrote:
> Similar to regular resizable BAR, VF BAR can also be resized.
>
> The structures are very similar, which means we can reuse most of the
> implementation.
There are differences in resizing which should be described (size calc
and mem decode check).
> Extend the pci_resize_resource() function to accept IOV resources.
> See PCIe r4.0, sec 9.3.7.4.
Can you update this to r6* please.
> Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
> ---
> drivers/pci/iov.c | 21 +++++++++++++++++++++
> drivers/pci/pci.c | 8 +++++++-
> drivers/pci/pci.h | 9 +++++++++
> drivers/pci/setup-res.c | 35 ++++++++++++++++++++++++++++++-----
> 4 files changed, 67 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index 985ea11339c45..cbf335725d4fb 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -154,6 +154,27 @@ 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)
> +{
> + if (!pci_resource_is_iov(resno)) {
> + pci_warn(dev, "%s is not an IOV resource\n",
> + pci_resource_name(dev, resno));
> + return;
> + }
> +
> + dev->sriov->barsz[pci_resource_num_to_vf_bar(resno)] = size;
> +}
> +
> +bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
> +{
> + u16 cmd;
> +
> + pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_CTRL, &cmd);
> +
> + return cmd & PCI_SRIOV_CTRL_MSE;
> +}
> +
> static void pci_read_vf_config_common(struct pci_dev *virtfn)
> {
> struct pci_dev *physfn = virtfn->physfn;
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index ff69f3d653ced..1fad9f4c54977 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3745,7 +3745,13 @@ static int pci_rebar_find_pos(struct pci_dev *pdev, int bar)
> unsigned int pos, nbars, i;
> u32 ctrl;
>
> - pos = pdev->rebar_cap;
> + if (pci_resource_is_iov(bar)) {
> + pos = pdev->physfn ? pdev->sriov->vf_rebar_cap : 0;
I'd explicitly do:
if (!pdev->physfn)
return -ENOTSUPP;
rather than relying pos = 0 triggering that return later on as the intent
is more obvious that way.
> + bar = pci_resource_num_to_vf_bar(bar);
> + } else {
> + pos = pdev->rebar_cap;
> + }
> +
> if (!pos)
> return -ENOTSUPP;
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index f44840ee3c327..643cd8c737f66 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -689,6 +689,9 @@ 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);
> +bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev);
> static inline bool pci_resource_is_iov(int resno)
> {
> return resno >= PCI_IOV_RESOURCES && resno <= PCI_IOV_RESOURCE_END;
> @@ -722,6 +725,12 @@ 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) { }
> +static inline bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
> +{
> + return false;
> +}
> static inline bool pci_resource_is_iov(int resno)
> {
> return false;
> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
> index c6657cdd06f67..d2b3ed51e8804 100644
> --- a/drivers/pci/setup-res.c
> +++ b/drivers/pci/setup-res.c
> @@ -423,13 +423,39 @@ void pci_release_resource(struct pci_dev *dev, int resno)
> }
> EXPORT_SYMBOL(pci_release_resource);
>
> +static bool pci_resize_is_memory_decoding_enabled(struct pci_dev *dev,
> + int resno)
> +{
> + u16 cmd;
> +
> + if (pci_resource_is_iov(resno))
> + return pci_iov_is_memory_decoding_enabled(dev);
> +
> + pci_read_config_word(dev, PCI_COMMAND, &cmd);
> +
> + return cmd & PCI_COMMAND_MEMORY;
> +}
> +
> +static void pci_resize_resource_set_size(struct pci_dev *dev, int resno,
> + int size)
> +{
> + 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);
> + }
> +}
> +
> int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> {
> struct resource *res = pci_resource_n(dev, resno);
> struct pci_host_bridge *host;
> int old, ret;
> u32 sizes;
> - u16 cmd;
>
> /* Check if we must preserve the firmware's resource assignment */
> host = pci_find_host_bridge(dev->bus);
> @@ -440,8 +466,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> if (!(res->flags & IORESOURCE_UNSET))
> return -EBUSY;
>
> - pci_read_config_word(dev, PCI_COMMAND, &cmd);
> - if (cmd & PCI_COMMAND_MEMORY)
> + if (pci_resize_is_memory_decoding_enabled(dev, resno))
> return -EBUSY;
>
> sizes = pci_rebar_get_possible_sizes(dev, resno);
> @@ -459,7 +484,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> if (ret)
> return ret;
>
> - resource_set_size(res, pci_rebar_size_to_bytes(size));
> + pci_resize_resource_set_size(dev, resno, size);
>
> /* Check if the new config works by trying to assign everything. */
> if (dev->bus->self) {
> @@ -471,7 +496,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
>
> error_resize:
> pci_rebar_set_size(dev, resno, old);
> - resource_set_size(res, pci_rebar_size_to_bytes(old));
> + pci_resize_resource_set_size(dev, resno, old);
> return ret;
> }
> EXPORT_SYMBOL(pci_resize_resource);
>
--
i.
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