[Xen-devel] Drivers cannot write to msix_iomem from DomU, is this right?

["Yi, Shunli" <syi@xxxxxxxxxxxx>]

Hi:

I’m using the Xen-3.3.1. and I find Xend doesn’t permit the DomU driver to access the msix_iomem.

 

"xend/server/pciif.py" : Line :342.

        if dev.msix:

            for (start, size) in dev.msix_iomem:

                start_pfn = start>>PAGE_SHIFT

                nr_pfns = (size+(PAGE_SIZE-1))>>PAGE_SHIFT

                log.debug('pci-msix: remove permission for 0x%x/0x%x 0x%x/0x%x' % \

                         (start,size, start_pfn, nr_pfns))

                rc = xc.domain_iomem_permission(domid = fe_domid,

                                                first_pfn = start_pfn,

                                                nr_pfns = nr_pfns,

                                                allow_access = False)

 

I haven’t wrote any driver code, but I think the driver should can write messages to the msix_iomem.

Because the driver will write some MSI information to the MSI register.

 

And I find following code in bnx2-1.8.5b:

File :                       bnx2.c  

Version:               1.8.5b

Function:             bnx2_enable_msix()

    bnx2_setup_msix_tbl(bp);

    REG_WR(bp, BNX2_PCI_MSIX_CONTROL, BNX2_MAX_MSIX_HW_VEC - 1);

    REG_WR(bp, BNX2_PCI_MSIX_TBL_OFF_BIR, BNX2_PCI_GRC_WINDOW2_BASE);

REG_WR(bp, BNX2_PCI_MSIX_PBA_OFF_BIT, BNX2_PCI_GRC_WINDOW3_BASE);

 

 

So, I think the msix_iomem should be always  writable for the DomU.

Am I Right?

 

 

Best Regards!

 

SHUNLI YI

WEBSENSE NETWORK SECURITY TECHNOLOGY R&D (BEIJING) CO. LTD.
ph: +8610.5884.4142

 

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