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[Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR. |
Date: |
Mon, 12 Oct 2009 16:11:29 +0200 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Mon, Oct 12, 2009 at 04:04:25PM +0200, Gleb Natapov wrote:
> On Mon, Oct 12, 2009 at 03:51:12PM +0200, Michael S. Tsirkin wrote:
> > On Mon, Oct 12, 2009 at 03:29:25PM +0200, Gleb Natapov wrote:
> > > On Mon, Oct 12, 2009 at 03:20:27PM +0200, Michael S. Tsirkin wrote:
> > > > Right. And there's another bug that I see and that is that size for I/O
> > > > BAR was calculated incorrectly: val & ~0xf is wrong for I/O as the size
> > > > could be 4 bytes. So here's a patch that addresses all 3 issues:
> > > > Ack?
> > > >
> > > Pleas do whatever spec recommends and use 0xffffffff to size the BAR.
> >
> > What we do is equivalent: since next thing we override the BAR value,
> > there's no reason for the save/restore dance. But if you like it this
> That what spec says if you are not trying to interpret it too hard.
> And simple is always better.
Implementation note is not a recommentation, just one way to do things.
We don't need to restore old BAR so no reason to do this, but
I won't lose sleep if we do this either. So go ahead.
>
> > way, OK. Send a patch. Note this applies to I/O and memory only,
> > ROM has to be sized the way I coded it.
> >
> > > Specs says this, linux does this, lets not be different.
> >
> > BTW, note that what linux does for ROM is incorrect:
> > the implementation note you cite only applies to I/O and memory BARs.
> > I'll send a patch to lkml when I have the time.
> >
> It does mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0; so it definitely
> treats ROM specially, You may argue that it shouldn't set bits 1-10
> though.
Right.
> The patch that currently in KVM bios (the one I've sent to seabios
> initially) uses the same technique to size the BAR as Linux kernel. The only
> thing missing is restoring of old value.
That, too. Also let's use symbolic constants, and fix size math:
(val & ~0xf) is wrong for both ROM and I/O.
> > > >
> > > > ---->
> > > >
> > > > Subject: [PATCH] seabios: fix low bits in ROM and I/O sizing
> > > >
> > > > This cleans up handling of low bits during BAR sizing,
> > > > to match PCI spec requirements, and to use symbolic
> > > > constants from pci_regs.h
> > > >
> > > > Issues fixed:
> > > > For ROM BARs, bit 0 is writeable (enable bit), which we not
> > > > only don't want to set, but it will stick and make us think
> > > > it's an I/O port resource.
> > > > Further, PCI spec defines the following bits as reserved:
> > > > - bit 1 in I/O BAR
> > > > - bits 10:1 in ROM BAR
> > > > and we should be careful and preserve any values there.
> > > > Bits 3:2 in I/O BAR might be writeable, so it
> > > > is wrong to mask them when calculating BAR size.
> > > >
> > > > Spec references:
> > > > See 6.2.5.1 for I/O and memory, and 6.2.5.2 for ROM,
> > > > 6.1 for reserved bit handling;
> > > > pages 225, 228 and 214 in PCI spec revision 3.0.
> > > >
> > > > See also Qemu pcbios commit 6ddb9f5c742b2b82b1755d7ec2a127f6e20e3806
> > > >
> > > > Original-by: Gleb Natapov <address@hidden>
> > > > Signed-off-by: Michael S. Tsirkin <address@hidden>
> > > >
> > > > diff --git a/src/pciinit.c b/src/pciinit.c
> > > > index 7d2ea00..f9ebd61 100644
> > > > --- a/src/pciinit.c
> > > > +++ b/src/pciinit.c
> > > > @@ -136,16 +136,23 @@ static void pci_bios_init_device(u16 bdf)
> > > > /* default memory mappings */
> > > > for (i = 0; i < PCI_NUM_REGIONS; i++) {
> > > > int ofs;
> > > > - u32 val, size;
> > > > -
> > > > + u32 val, mask, size;
> > > > if (i == PCI_ROM_SLOT)
> > > > ofs = PCI_ROM_ADDRESS;
> > > > else
> > > > ofs = PCI_BASE_ADDRESS_0 + i * 4;
> > > > - pci_config_writel(bdf, ofs, 0xffffffff);
> > > > +
> > > > + val = pci_config_readl(bdf, ofs);
> > > > + if (i == PCI_ROM_SLOT)
> > > > + mask = PCI_ROM_ADDRESS_MASK;
> > > > + else if (val & PCI_BASE_ADDRESS_SPACE_IO)
> > > > + mask = PCI_BASE_ADDRESS_IO_MASK;
> > > > + else
> > > > + mask = PCI_BASE_ADDRESS_MEM_MASK;
> > > > + pci_config_writel(bdf, ofs, val | mask);
> > > > val = pci_config_readl(bdf, ofs);
> > > > if (val != 0) {
> > > > - size = (~(val & ~0xf)) + 1;
> > > > + size = (~(val & mask)) + 1;
> > > > if (val & PCI_BASE_ADDRESS_SPACE_IO)
> > > > paddr = &pci_bios_io_addr;
> > > > else if (size >= 0x04000000)
> > > > --
> > > > 1.6.5.rc2
> > > >
> > >
> > > --
> > > Gleb.
>
> --
> Gleb.
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., (continued)
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Gleb Natapov, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Michael S. Tsirkin, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Michael S. Tsirkin, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Gleb Natapov, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Michael S. Tsirkin, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Gleb Natapov, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Michael S. Tsirkin, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Gleb Natapov, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Michael S. Tsirkin, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Gleb Natapov, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR.,
Michael S. Tsirkin <=
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Gleb Natapov, 2009/10/12
- [Qemu-devel] Re: [PATCH 3/5] Use the correct mask to size the PCI option ROM BAR., Michael S. Tsirkin, 2009/10/12
- [Qemu-devel] seabios: fix low bits in ROM and I/O sizing, Michael S. Tsirkin, 2009/10/12
- [Qemu-devel] Re: seabios: fix low bits in ROM and I/O sizing, Gleb Natapov, 2009/10/13
- Re: [Qemu-devel] Re: seabios: fix low bits in ROM and I/O sizing, Kevin O'Connor, 2009/10/14
[Qemu-devel] [PATCH 4/5] Make MMIO address page aligned in guest., Gleb Natapov, 2009/10/11