linux-kernel - Re: [PATCH v2] PCI: endpoint: Skip odd BAR when skipping 64bit BAR

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Message-ID: <baa68439-f703-a453-34a2-24387bb9112d@ti.com>
Date:   Fri, 24 May 2019 14:19:39 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Alan Mikhak <alan.mikhak@...ive.com>, <linux-pci@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <lorenzo.pieralisi@....com>,
        <linux-riscv@...ts.infradead.org>,
        Palmer Dabbelt <palmer@...ive.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        <gustavo.pimentel@...opsys.com>, <wen.yang99@....com.cn>,
        <kjlu@....edu>
Subject: Re: [PATCH v2] PCI: endpoint: Skip odd BAR when skipping 64bit BAR

Hi,

On 24/05/19 5:25 AM, Alan Mikhak wrote:
> +Bjorn Helgaas, +Gustavo Pimentel, +Wen Yang, +Kangjie Lu
> 
> On Thu, May 23, 2019 at 2:55 PM Alan Mikhak <alan.mikhak@...ive.com> wrote:
>>
>> Always skip odd bar when skipping 64bit BARs in pci_epf_test_set_bar()
>> and pci_epf_test_alloc_space().
>>
>> Otherwise, pci_epf_test_set_bar() will call pci_epc_set_bar() on odd loop
>> index when skipping reserved 64bit BAR. Moreover, pci_epf_test_alloc_space()
>> will call pci_epf_alloc_space() on bind for odd loop index when BAR is 64bit
>> but leaks on subsequent unbind by not calling pci_epf_free_space().
>>
>> Signed-off-by: Alan Mikhak <alan.mikhak@...ive.com>
>> Reviewed-by: Paul Walmsley <paul.walmsley@...ive.com>
>> ---
>>  drivers/pci/endpoint/functions/pci-epf-test.c | 25 ++++++++++++-------------
>>  1 file changed, 12 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>> index 27806987e93b..96156a537922 100644
>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>> @@ -389,7 +389,7 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
>>
>>  static int pci_epf_test_set_bar(struct pci_epf *epf)
>>  {
>> -       int bar;
>> +       int bar, add;
>>         int ret;
>>         struct pci_epf_bar *epf_bar;
>>         struct pci_epc *epc = epf->epc;
>> @@ -400,8 +400,14 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
>>
>>         epc_features = epf_test->epc_features;
>>
>> -       for (bar = BAR_0; bar <= BAR_5; bar++) {
>> +       for (bar = BAR_0; bar <= BAR_5; bar += add) {
>>                 epf_bar = &epf->bar[bar];
>> +               /*
>> +                * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64
>> +                * if the specific implementation required a 64-bit BAR,
>> +                * even if we only requested a 32-bit BAR.
>> +                */

set_bar shouldn't set PCI_BASE_ADDRESS_MEM_TYPE_64. If a platform supports only
64-bit BAR, that should be specified in epc_features bar_fixed_64bit member.

Thanks
Kishon