Re: [RFC PATCH v2 05/21][SeaBIOS] pciinit: Fix pcimem_start value
On 07/11/12 18:45, Vasilis Liaskovitis wrote:
Hi,
On Wed, Jul 11, 2012 at 01:56:19PM +0200, Gerd Hoffmann wrote:
On 07/11/12 12:31, Vasilis Liaskovitis wrote:
In order to hotplug memory between RamSize and BUILD_PCIMEM_START, the pci
window needs to start at BUILD_PCIMEM_START (0xe000).
Otherwise, the guest cannot online new dimms at those ranges due to pci_root
window conflicts. (workaround for linux guest is booting with pci=nocrs)
static void pci_bios_map_devices(struct pci_bus *busses)
{
-pcimem_start = RamSize;
+pcimem_start = BUILD_PCIMEM_START;
It isn't that simple. For the 32bit pci window it will work, but will
leaves address space unused instead of assigning it to the 32bit pci
window. For the 64bit pci window it will not work.
You have to walk the dimms and figure what the highest used address is,
for both below-4g and above-4g. Then fill two variable with it and make
the pci init code use that instead of RamSize and RamSizeOver4G.
I see. I already have these values values computed in qemu-kvm, so I can pass
them in a paravirt struct, or infer them from the dimm/srat paravirt info
that I
already pass to seabios.
I'd suggest to infer from the dimm info, to limit the amout of
information which needs to be passed from qemu to seabios.
If i understand correctly, we would like the pcimem windows to use the maximum
possible address space (constrained by the exact dimms/ranges which are
defined)
instead of leaving unused space.
Yes, for the 32bit pci window.
The 64bit pci window is mapped above all memory, and it must likewise
consider defined+unfilled dimms so the start address doesn't collide
with memory hot-plugged above 4G later on.
cheers,
Gerd
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Re: [RFC PATCH v2 05/21][SeaBIOS] pciinit: Fix pcimem_start value
On Thu, Jul 12, 2012 at 09:22:14AM +0200, Gerd Hoffmann wrote:
On 07/11/12 18:45, Vasilis Liaskovitis wrote:
Hi,
On Wed, Jul 11, 2012 at 01:56:19PM +0200, Gerd Hoffmann wrote:
On 07/11/12 12:31, Vasilis Liaskovitis wrote:
In order to hotplug memory between RamSize and BUILD_PCIMEM_START, the pci
window needs to start at BUILD_PCIMEM_START (0xe000).
Otherwise, the guest cannot online new dimms at those ranges due to
pci_root
window conflicts. (workaround for linux guest is booting with pci=nocrs)
static void pci_bios_map_devices(struct pci_bus *busses)
{
-pcimem_start = RamSize;
+pcimem_start = BUILD_PCIMEM_START;
It isn't that simple. For the 32bit pci window it will work, but will
leaves address space unused instead of assigning it to the 32bit pci
window. For the 64bit pci window it will not work.
You have to walk the dimms and figure what the highest used address is,
for both below-4g and above-4g. Then fill two variable with it and make
the pci init code use that instead of RamSize and RamSizeOver4G.
I see. I already have these values values computed in qemu-kvm, so I can
pass
them in a paravirt struct, or infer them from the dimm/srat paravirt info
that I
already pass to seabios.
I'd suggest to infer from the dimm info, to limit the amout of
information which needs to be passed from qemu to seabios.
ok.Currently dimm info is processed in bios_init_tables(), which is called after
pci_setup(). I 'll see if i can do the processing earlier.
If i understand correctly, we would like the pcimem windows to use the
maximum
possible address space (constrained by the exact dimms/ranges which are
defined)
instead of leaving unused space.
Yes, for the 32bit pci window.
The 64bit pci window is mapped above all memory, and it must likewise
consider defined+unfilled dimms so the start address doesn't collide
with memory hot-plugged above 4G later on.
yes, understood.
thanks,
- Vasilis
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Re: [RFC PATCH v2 05/21][SeaBIOS] pciinit: Fix pcimem_start value
On 07/11/12 12:31, Vasilis Liaskovitis wrote:
In order to hotplug memory between RamSize and BUILD_PCIMEM_START, the pci
window needs to start at BUILD_PCIMEM_START (0xe000).
Otherwise, the guest cannot online new dimms at those ranges due to pci_root
window conflicts. (workaround for linux guest is booting with pci=nocrs)
static void pci_bios_map_devices(struct pci_bus *busses)
{
-pcimem_start = RamSize;
+pcimem_start = BUILD_PCIMEM_START;
It isn't that simple. For the 32bit pci window it will work, but will
leaves address space unused instead of assigning it to the 32bit pci
window. For the 64bit pci window it will not work.
You have to walk the dimms and figure what the highest used address is,
for both below-4g and above-4g. Then fill two variable with it and make
the pci init code use that instead of RamSize and RamSizeOver4G.
cheers,
Gerd
--
To unsubscribe from this list: send the line unsubscribe kvm in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [RFC PATCH v2 05/21][SeaBIOS] pciinit: Fix pcimem_start value
Hi,
On Wed, Jul 11, 2012 at 01:56:19PM +0200, Gerd Hoffmann wrote:
On 07/11/12 12:31, Vasilis Liaskovitis wrote:
In order to hotplug memory between RamSize and BUILD_PCIMEM_START, the pci
window needs to start at BUILD_PCIMEM_START (0xe000).
Otherwise, the guest cannot online new dimms at those ranges due to pci_root
window conflicts. (workaround for linux guest is booting with pci=nocrs)
static void pci_bios_map_devices(struct pci_bus *busses)
{
-pcimem_start = RamSize;
+pcimem_start = BUILD_PCIMEM_START;
It isn't that simple. For the 32bit pci window it will work, but will
leaves address space unused instead of assigning it to the 32bit pci
window. For the 64bit pci window it will not work.
You have to walk the dimms and figure what the highest used address is,
for both below-4g and above-4g. Then fill two variable with it and make
the pci init code use that instead of RamSize and RamSizeOver4G.
I see. I already have these values values computed in qemu-kvm, so I can pass
them in a paravirt struct, or infer them from the dimm/srat paravirt info that I
already pass to seabios.
If i understand correctly, we would like the pcimem windows to use the maximum
possible address space (constrained by the exact dimms/ranges which are defined)
instead of leaving unused space.
thanks,
- Vasilis
--
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the body of a message to majord...@vger.kernel.org
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