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Date: Tue, 18 Sep 2012 12:25:50 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Jan Beulich <JBeulich@...e.com>
Cc: xen-devel <xen-devel@...ts.xen.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] xen-pciback: support wild cards in slot specifications
On Tue, Sep 18, 2012 at 12:29:03PM +0100, Jan Beulich wrote:
> Particularly for hiding sets of SR-IOV devices, specifying them all
> individually is rather cumbersome. Therefore, allow function and slot
> numbers to be replaced by a wildcard character ('*').
>
> Unfortunately this gets complicated by the in-kernel sscanf()
> implementation not being really standard conformant - matching of
> plain text tails cannot be checked by the caller (a patch to overcome
> this will be sent shortly, and a follow-up patch for simplifying the
> code is planned to be sent when that fixed went upstream).
applied for 3.7
>
> Signed-off-by: Jan Beulich <jbeulich@...e.com>
>
> ---
> drivers/xen/xen-pciback/pci_stub.c | 89 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 82 insertions(+), 7 deletions(-)
>
> --- 3.6-rc6/drivers/xen/xen-pciback/pci_stub.c
> +++ 3.6-rc6-xen-pciback-wildcard/drivers/xen/xen-pciback/pci_stub.c
> @@ -897,17 +897,41 @@ static inline int str_to_slot(const char
> int *slot, int *func)
> {
> int err;
> + char wc = '*';
>
> err = sscanf(buf, " %x:%x:%x.%x", domain, bus, slot, func);
> - if (err == 4)
> + switch (err) {
> + case 3:
> + *func = -1;
> + err = sscanf(buf, " %x:%x:%x.%c", domain, bus, slot, &wc);
> + break;
> + case 2:
> + *slot = *func = -1;
> + err = sscanf(buf, " %x:%x:*.%c", domain, bus, &wc);
> + if (err >= 2)
> + ++err;
> + break;
> + }
> + if (err == 4 && wc == '*')
> return 0;
> else if (err < 0)
> return -EINVAL;
>
> /* try again without domain */
> *domain = 0;
> + wc = '*';
> err = sscanf(buf, " %x:%x.%x", bus, slot, func);
> - if (err == 3)
> + switch (err) {
> + case 2:
> + *func = -1;
> + err = sscanf(buf, " %x:%x.%c", bus, slot, &wc);
> + break;
> + case 1:
> + *slot = *func = -1;
> + err = sscanf(buf, " %x:*.%c", bus, &wc) + 1;
> + break;
> + }
> + if (err == 3 && wc == '*')
> return 0;
>
> return -EINVAL;
> @@ -930,6 +954,19 @@ static int pcistub_device_id_add(int dom
> {
> struct pcistub_device_id *pci_dev_id;
> unsigned long flags;
> + int rc = 0;
> +
> + if (slot < 0) {
> + for (slot = 0; !rc && slot < 32; ++slot)
> + rc = pcistub_device_id_add(domain, bus, slot, func);
> + return rc;
> + }
> +
> + if (func < 0) {
> + for (func = 0; !rc && func < 8; ++func)
> + rc = pcistub_device_id_add(domain, bus, slot, func);
> + return rc;
> + }
>
> pci_dev_id = kmalloc(sizeof(*pci_dev_id), GFP_KERNEL);
> if (!pci_dev_id)
> @@ -952,15 +989,15 @@ static int pcistub_device_id_add(int dom
> static int pcistub_device_id_remove(int domain, int bus, int slot, int func)
> {
> struct pcistub_device_id *pci_dev_id, *t;
> - int devfn = PCI_DEVFN(slot, func);
> int err = -ENOENT;
> unsigned long flags;
>
> spin_lock_irqsave(&device_ids_lock, flags);
> list_for_each_entry_safe(pci_dev_id, t, &pcistub_device_ids,
> slot_list) {
> - if (pci_dev_id->domain == domain
> - && pci_dev_id->bus == bus && pci_dev_id->devfn == devfn) {
> + if (pci_dev_id->domain == domain && pci_dev_id->bus == bus
> + && (slot < 0 || PCI_SLOT(pci_dev_id->devfn) == slot)
> + && (func < 0 || PCI_FUNC(pci_dev_id->devfn) == func)) {
> /* Don't break; here because it's possible the same
> * slot could be in the list more than once
> */
> @@ -1216,6 +1253,10 @@ static ssize_t permissive_add(struct dev
> err = str_to_slot(buf, &domain, &bus, &slot, &func);
> if (err)
> goto out;
> + if (slot < 0 || func < 0) {
> + err = -EINVAL;
> + goto out;
> + }
> psdev = pcistub_device_find(domain, bus, slot, func);
> if (!psdev) {
> err = -ENODEV;
> @@ -1297,17 +1338,51 @@ static int __init pcistub_init(void)
>
> if (pci_devs_to_hide && *pci_devs_to_hide) {
> do {
> + char wc = '*';
> +
> parsed = 0;
>
> err = sscanf(pci_devs_to_hide + pos,
> " (%x:%x:%x.%x) %n",
> &domain, &bus, &slot, &func, &parsed);
> - if (err != 4) {
> + switch (err) {
> + case 3:
> + func = -1;
> + err = sscanf(pci_devs_to_hide + pos,
> + " (%x:%x:%x.%c) %n",
> + &domain, &bus, &slot, &wc,
> + &parsed);
> + break;
> + case 2:
> + slot = func = -1;
> + err = sscanf(pci_devs_to_hide + pos,
> + " (%x:%x:*.%c) %n",
> + &domain, &bus, &wc, &parsed) + 1;
> + break;
> + }
> +
> + if (err != 4 || wc != '*') {
> domain = 0;
> + wc = '*';
> err = sscanf(pci_devs_to_hide + pos,
> " (%x:%x.%x) %n",
> &bus, &slot, &func, &parsed);
> - if (err != 3)
> + switch (err) {
> + case 2:
> + func = -1;
> + err = sscanf(pci_devs_to_hide + pos,
> + " (%x:%x.%c) %n",
> + &bus, &slot, &wc,
> + &parsed);
> + break;
> + case 1:
> + slot = func = -1;
> + err = sscanf(pci_devs_to_hide + pos,
> + " (%x:*.%c) %n",
> + &bus, &wc, &parsed) + 1;
> + break;
> + }
> + if (err != 3 || wc != '*')
> goto parse_error;
> }
>
>
--
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