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[Qemu-devel] Re: [PATCH 12/25] pci: 64bit bar support.
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] Re: [PATCH 12/25] pci: 64bit bar support. |
Date: |
Mon, 5 Oct 2009 12:08:42 +0200 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Mon, Oct 05, 2009 at 06:45:06PM +0900, Isaku Yamahata wrote:
> On Sun, Oct 04, 2009 at 12:26:46PM +0200, Michael S. Tsirkin wrote:
> > On Sat, Oct 03, 2009 at 05:16:04AM +0900, Isaku Yamahata wrote:
> > > implemented pci 64bit bar support.
> > >
> > > Signed-off-by: Isaku Yamahata <address@hidden>
> > > ---
> > > hw/pci.c | 41 ++++++++++++++++++++++++++++++++++++-----
> > > hw/pci.h | 9 +++++++++
> > > 2 files changed, 45 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/hw/pci.c b/hw/pci.c
> > > index 510fad2..75af2cd 100644
> > > --- a/hw/pci.c
> > > +++ b/hw/pci.c
> > > @@ -427,8 +427,13 @@ void pci_register_bar(PCIDevice *pci_dev, int
> > > region_num,
> > > addr = 0x10 + region_num * 4;
> > > }
> > > pci_set_long(pci_dev->config + addr, type);
> > > - pci_set_long(pci_dev->wmask + addr, wmask & 0xffffffff);
> > > - pci_set_long(pci_dev->cmask + addr, 0xffffffff);
> > > + if (pci_bar_is_64bit(r)) {
> > > + pci_set_quad(pci_dev->wmask + addr, wmask);
> > > + pci_set_quad(pci_dev->cmask + addr, ~0ULL);
> > > + } else {
> > > + pci_set_long(pci_dev->wmask + addr, wmask & 0xffffffff);
> > > + pci_set_long(pci_dev->cmask + addr, 0xffffffff);
> > > + }
> > > }
> > >
> > > static void pci_update_mappings(PCIDevice *d)
> > > @@ -462,7 +467,11 @@ static void pci_update_mappings(PCIDevice *d)
> > > }
> > > } else {
> > > if (cmd & PCI_COMMAND_MEMORY) {
> > > - new_addr = pci_get_long(d->config + config_ofs);
> > > + if (pci_bar_is_64bit(r)) {
> > > + new_addr = pci_get_quad(d->config + config_ofs);
> > > + } else {
> > > + new_addr = pci_get_long(d->config + config_ofs);
> > > + }
> > > /* the ROM slot has a specific enable bit */
> > > if (i == PCI_ROM_SLOT && !(new_addr & 1))
> > > goto no_mem_map;
> > > @@ -477,7 +486,7 @@ static void pci_update_mappings(PCIDevice *d)
> > >
> > > /* keep old behaviour
> > > * without this, PC ide doesn't work well. */
> > > - last_addr >= UINT32_MAX) {
> > > + (!pci_bar_is_64bit(r) && last_addr >=
> > > UINT32_MAX)) {
> > > new_addr = PCI_BAR_UNMAPPED;
> >
> > I don't really understand what is this doing
>
> I'll add a comment above the line in the patch.
>
> In a word, it is a work around of qemu implementation limitation.
> So far bar was only 32bit, just wrapping around check worked.
> But now it's 64bit, explicit 4G check becomes needed.
> OS writes all one bits to BAR register to detect its size
> meaning that memory 32 bit bar is once set right below 4GB,
> and then maps the area to where OS really want it to exist.
PCI spec actually says:
Decode (I/O or memory) of a register is disabled
via the command register before sizing a Base Address register.
Is the OS in question out of spec then?
> Since mapping memory space at 4G causes troubles,
What kind of trouble? Does it happen to clash with the -1 value we use for
invalid regions? Would changing invalid region to some other value help?
> pci_update_mapping() have to work around not to map right below 4G.
Thats out of spec, isn't it? Please add a TODO so we'll remember to fix it.
>
> > > }
> > > } else {
> > > @@ -736,7 +745,29 @@ static void pci_info_device(PCIDevice *d)
> > > monitor_printf(mon, "I/O at 0x%04"FMT_pcibus"
> > > [0x%04"FMT_pcibus"].\n",
> > > r->addr, r->addr + r->size - 1);
> > > } else {
> > > - monitor_printf(mon, "32 bit memory at 0x%08"FMT_pcibus"
> > > [0x%08"FMT_pcibus"].\n",
> > > + const char *type;
> > > + const char* prefetch;
> > > +
> > > + switch (r->type & PCI_ADDRESS_SPACE_MEM_TYPE_MASK) {
> > > + case PCI_ADDRESS_SPACE_MEM:
> > > + type = "32 bit";
> > > + break;
> > > + case PCI_ADDRESS_SPACE_MEM_64:
> > > + type = "64 bit";
> > > + break;
> > > + default:
> > > + type = "unknown";
> > > + break;
> >
> > this default is just dead code?
> > How about type = is_64bit() ? "64" : "32"
> >
> > > + }
> > > +
> > > + prefetch = "";
> > > + if (r->type & PCI_ADDRESS_SPACE_MEM_PREFETCH) {
> > > + prefetch = " prefetchable";
> > > + }
> > > +
> > > + monitor_printf(mon, "%s%s memory at "
> > > + "0x%08"FMT_pcibus"
> > > [0x%08"FMT_pcibus"].\n",
> > > + type, prefetch,
> > > r->addr, r->addr + r->size - 1);
> > > }
> > > }
> > > diff --git a/hw/pci.h b/hw/pci.h
> > > index c209f34..0455b30 100644
> > > --- a/hw/pci.h
> > > +++ b/hw/pci.h
> > > @@ -84,6 +84,8 @@ typedef int PCIUnregisterFunc(PCIDevice *pci_dev);
> > >
> > > #define PCI_ADDRESS_SPACE_MEM 0x00
> > > #define PCI_ADDRESS_SPACE_IO 0x01
> > > +#define PCI_ADDRESS_SPACE_MEM_64 0x04 /* 64 bit address */
> >
> > PCI_ADDRESS_MEM_TYPE_64 is a better name: it's a type of memory,
> > not a separate address space.
> >
> > Actually, we should probably just reuse macros from pci_regs.h
> > and put them with rest of macros imported from there.
> > The list of relevant macros (prefixes with // these that we don't use
> > and probably shouldn't put in header):
> >
> > #define PCI_BASE_ADDRESS_SPACE 0x01 /* 0 = memory, 1 = I/O
> > */
> > #define PCI_BASE_ADDRESS_SPACE_IO 0x01
> > #define PCI_BASE_ADDRESS_SPACE_MEMORY 0x00
> > //#define PCI_BASE_ADDRESS_MEM_TYPE_MASK 0x06
> > //#define PCI_BASE_ADDRESS_MEM_TYPE_32 0x00 /* 32 bit address */
> > //#define PCI_BASE_ADDRESS_MEM_TYPE_1M 0x02 /* Below 1M [obsolete]
> > */
> > #define PCI_BASE_ADDRESS_MEM_TYPE_64 0x04 /* 64 bit address */
> > #define PCI_BASE_ADDRESS_MEM_PREFETCH 0x08 /* prefetchable? */
> >
> >
> > > +#define PCI_ADDRESS_SPACE_MEM_TYPE_MASK 0x06
> >
> > This one is used in pci_regs.h to include 64 bit an 1M.
> > what do you use it for?
> > It seems unnecessary.
>
> Will drop unused ones.
>
>
> > > #define PCI_ADDRESS_SPACE_MEM_PREFETCH 0x08
> > >
> > > typedef struct PCIIORegion {
> > > @@ -94,6 +96,13 @@ typedef struct PCIIORegion {
> > > PCIMapIORegionFunc *map_func;
> > > } PCIIORegion;
> > >
> > > +static inline int pci_bar_is_64bit(const PCIIORegion *r)
> >
> > Is it used outside pci.c? If no, do not put in pci.h
> >
> > > +{
> > > + return !(r->type & PCI_ADDRESS_SPACE_IO) &&
> > > + ((r->type & PCI_ADDRESS_SPACE_MEM_TYPE_MASK) ==
> > > + PCI_ADDRESS_SPACE_MEM_64);
> >
> > This is probably wrong: we should only care about the MEM_64 bit.
> >
> > Why don't we just return (r->type & PCI_BASE_ADDRESS_MEM_TYPE_64)?
> > And this function is simple enough to be open-coded then.
>
> Will use PCI_ADDRESS_MEM_TYPE_64.
> Since it's not a bit,
> (>type & PCI_ADDRESS_SPACE_MEM_TYPE_MASK) == PCI_ADDRESS_SPACE_MEM_TYPE_64
> makes sense.
It is a bit. PCI_ADDRESS_SPACE_MEM_TYPE_MASK also checks for below 1M
which we don't define and so do not care about.
> > Nit: we don't need () around the == comparison.
> >
> > > +}
> > > +
> > > #define PCI_ROM_SLOT 6
> > > #define PCI_NUM_REGIONS 7
> > >
> >
>
> --
> yamahata
- [Qemu-devel] Re: [PATCH 21/25] pci: make bar update function aware of pci bridge., (continued)
[Qemu-devel] [PATCH 01/25] pci: fix PCI_DPRINTF() wrt variadic macro., Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 06/25] pci: define a constant to represent a unmapped bar and use it., Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 17/25] pci: fix pci_default_write_config(), Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 12/25] pci: 64bit bar support., Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 08/25] pci: use helper functions to access pci config space., Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 10/25] pci: introduce FMT_pcibus for printf format for pcibus_t., Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 14/25] pci: factor out the logic to get pci device from address., Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 25/25] pci/monitor: print out bridge's filtering values and so on., Isaku Yamahata, 2009/10/02
[Qemu-devel] [PATCH 04/25] pci: use the symbolic constant, PCI_ROM_ADDRESS_ENABLE instead of 1., Isaku Yamahata, 2009/10/02