On 2014/8/15 11:51, Konrad Rzeszutek Wilk wrote:
> On Fri, Aug 15, 2014 at 11:14:37AM +0800, Yijing Wang wrote:
>> We had cached the MSI msg in __write_msi_msg(),
>> so we should retrieve the cached MSI msg directly,
>> not to access the MSI address/data hardware registers
>> again.
>
> Is this fixing a particular problem?
>
> Could you kindly explain to me when you do the __write_msi_msg
> before doing an read_msi_msg? The order of operation in this
> function is read, and then write.
Hi Konrad,
Thanks for your review and comments. It looks like I made a mistake.
Before I thought xen_hvm_setup_msi_irqs() here worked like restore MSI irq,
but it seems not in real. Since every time we call the setup MSI irq function,
the msi_desc always new allocated, so here should use read_msi_msg(),
I'm sorry for my mistake. :(
Bjorn, please drop this one.
Thanks!
Yijing.
>
>>
>> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
>> CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>> CC: xen-devel@xxxxxxxxxxxxxxxxxxxx
>> ---
>> arch/x86/pci/xen.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>> index 4656099..7a74404 100644
>> --- a/arch/x86/pci/xen.c
>> +++ b/arch/x86/pci/xen.c
>> @@ -228,7 +228,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>> return 1;
>>
>> list_for_each_entry(msidesc, &dev->msi_list, list) {
>> - read_msi_msg(msidesc, &msg);
>> + get_cached_msi_msg(msidesc, &msg);
>> pirq = MSI_ADDR_EXT_DEST_ID(msg.address_hi) |
>> ((msg.address_lo >> MSI_ADDR_DEST_ID_SHIFT) & 0xff);
>> if (msg.data != XEN_PIRQ_MSI_DATA ||
>> --
>> 1.7.1
>>
>
>
--
Thanks!
Yijing
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