On 13/11/2020 10:25, Jan Beulich wrote:
On 13.11.2020 07:32, Oleksandr Andrushchenko wrote:
On 11/12/20 4:46 PM, Roger Pau Monné wrote:
On Thu, Nov 12, 2020 at 01:16:10PM +0000, Oleksandr Andrushchenko wrote:
On 11/12/20 11:40 AM, Roger Pau Monné wrote:
On Mon, Nov 09, 2020 at 02:50:27PM +0200, Oleksandr Andrushchenko wrote:
From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
+static uint32_t bar_read_dispatch(const struct pci_dev *pdev, unsigned int reg,
+ void *data)
+{
+ struct vpci_bar *vbar, *bar = data;
+
+ if ( is_hardware_domain(current->domain) )
+ return bar_read_hwdom(pdev, reg, data);
+
+ vbar = get_vpci_bar(current->domain, pdev, bar->index);
+ if ( !vbar )
+ return ~0;
+
+ return bar_read_guest(pdev, reg, vbar);
+}
+
+static void bar_write_dispatch(const struct pci_dev *pdev, unsigned int reg,
+ uint32_t val, void *data)
+{
+ struct vpci_bar *bar = data;
+
+ if ( is_hardware_domain(current->domain) )
+ bar_write_hwdom(pdev, reg, val, data);
+ else
+ {
+ struct vpci_bar *vbar = get_vpci_bar(current->domain, pdev,
bar->index);
+
+ if ( !vbar )
+ return;
+ bar_write_guest(pdev, reg, val, vbar);
+ }
+}
You should assign different handlers based on whether the domain that
has the device assigned is a domU or the hardware domain, rather than
doing the selection here.
Hm, handlers are assigned once in init_bars and this function is only called
for hwdom, so there is no way I can do that for the guests. Hence, the
dispatcher
I think we might want to reset the vPCI handlers when a devices gets
assigned and deassigned.
In ARM case init_bars is called too early: PCI device assignment is currently
initiated by Domain-0' kernel and is done *before* PCI devices are given memory
ranges and BARs assigned:
[ 0.429514] pci_bus 0000:00: root bus resource [bus 00-ff]
[ 0.429532] pci_bus 0000:00: root bus resource [io 0x0000-0xfffff]
[ 0.429555] pci_bus 0000:00: root bus resource [mem 0xfe200000-0xfe3fffff]
[ 0.429575] pci_bus 0000:00: root bus resource [mem 0x30000000-0x37ffffff]
[ 0.429604] pci_bus 0000:00: root bus resource [mem 0x38000000-0x3fffffff
pref]
[ 0.429670] pci 0000:00:00.0: enabling Extended Tags
[ 0.453764] pci 0000:00:00.0: -------------------- BUS_NOTIFY_ADD_DEVICE
< init_bars >
[ 0.453793] pci 0000:00:00.0: -- IRQ 0
[ 0.458825] pci 0000:00:00.0: Failed to add - passthrough or MSI/MSI-X might
fail!
[ 0.471790] pci 0000:01:00.0: -------------------- BUS_NOTIFY_ADD_DEVICE
< init_bars >
[ 0.471821] pci 0000:01:00.0: -- IRQ 255
[ 0.476809] pci 0000:01:00.0: Failed to add - passthrough or MSI/MSI-X might
fail!
< BAR assignments below >
[ 0.488233] pci 0000:00:00.0: BAR 14: assigned [mem 0xfe200000-0xfe2fffff]
[ 0.488265] pci 0000:00:00.0: BAR 15: assigned [mem 0x38000000-0x380fffff
pref]
In case of x86 this is pretty much ok as BARs are already in place, but for ARM
we
need to take care and re-setup vPCI BARs for hwdom.
Even on x86 there's no guarantee that all devices have their BARs set
up by firmware.
In a subsequent reply you've suggested to move init_bars from "add" to
"assign", but I'm having trouble seeing what this would change: It's
not Dom0 controlling assignment (to itself), but Xen assigns the device
towards the end of pci_add_device().
Things are getting even more
complicated if the host PCI bridge is not ECAM like, so you cannot set
mmio_handlers
and trap hwdom's access to the config space to update BARs etc. This is why I
have that
ugly hack for rcar_gen3 to read actual BARs for hwdom.
How to config space accesses work there? The latest for MSI/MSI-X it'll
be imperative that Xen be able to intercept config space writes.
I am not sure to understand your last sentence. Are you saying that we
always need to trap access to MSI/MSI-X message in order to sanitize it?
If one is using the GICv3 ITS (I haven't investigated other MSI
controller), then I don't believe you need to sanitize the MSI/MSI-X
message in most of the situation.
Cheers,
--
Julien Grall
