On 03/14/16 09:07, Marcel Apfelbaum wrote:
On 03/14/2016 03:42 AM, Laszlo Ersek wrote:
In build_crs(), the calculation & merging of the ranges already
happens in
64-bit, but the entry boundaries are silently truncated to 32-bit in the
call to aml_dword_memory(). Use aml_qword_memory() when necessary -- this
fixes 64-bit BARs behind PXBs.
Hi Laszlo,
Thanks for the patch.
Please see below some comments.
Cc: Marcel Apfelbaum <address@hidden>
Cc: Michael S. Tsirkin <address@hidden>
Signed-off-by: Laszlo Ersek <address@hidden>
---
hw/i386/acpi-build.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index b88800883944..3157cc36db98 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -938,13 +938,25 @@ static Aml *build_crs(PCIHostState *host,
crs_range_merge(host_mem_ranges);
for (i = 0; i < host_mem_ranges->len; i++) {
+ Aml *mem;
+ uint64_t length;
+
entry = g_ptr_array_index(host_mem_ranges, i);
- aml_append(crs,
- aml_dword_memory(AML_POS_DECODE, AML_MIN_FIXED,
- AML_MAX_FIXED, AML_NON_CACHEABLE,
- AML_READ_WRITE,
- 0, entry->base, entry->limit, 0,
- entry->limit - entry->base + 1));
+ length = entry->limit - entry->base + 1;
+ if (entry->limit <= UINT32_MAX && length <= UINT32_MAX) {
Why do we need to check the length if we've already checked the
entry->limit ?
For mathematical completeness :) When limit is <= UINT32_MAX, that
implies that base is also <= UINT32_MAX, so that's why I'm not checking
base. However, length = limit - base + 1, and in theory, it can mean
length = UINT32_MAX - 0 + 1, which doesn't fit in a uint32_t.
In other words, limit is inclusive but length is exclusive, so it can be
1 higher (when base is 0).
(And checking only length is also not sufficient, of course.)
+ mem = aml_dword_memory(AML_POS_DECODE, AML_MIN_FIXED,
+ AML_MAX_FIXED, AML_NON_CACHEABLE,
+ AML_READ_WRITE,
+ 0, entry->base, entry->limit, 0,
+ length);
+ } else {
+ mem = aml_qword_memory(AML_POS_DECODE, AML_MIN_FIXED,
+ AML_MAX_FIXED, AML_NON_CACHEABLE,
+ AML_READ_WRITE,
+ 0, entry->base, entry->limit, 0,
+ length);
+ }
+ aml_append(crs, mem);
crs_range_insert(mem_ranges, entry->base, entry->limit);
}
g_ptr_array_free(host_mem_ranges, true);
I think it is correct, but this also means the mem_ranges array can have
64-bit ranges =>
the 'crs_replace_with_free_ranges' call for mem_ranges is also incorrect
because
it assumes all the ranges are between [pci->w32.begin, pci->w32.end - 1].
Hm. :)
And of course this would also interfere with the crs building for pci->w64.
We can't assign all the [pci->w64.begin, pci->w64.end - 1] range to bus
0 anymore,
we need to take out the ranges used by pxbs. (same as we did for pci->w32)
Indeed, this is one of the pxb limitations, supporting only 32bit BARs
Ah! Now that was a question I considered, but I couldn't decide if it
was a known / by-design choice (or limitation), or just an oversight in
the code. I figured I'd ask with a patch. :)
and your patch is going in the right direction.
Do you want to continue it? I will not be available for one week, but I
can take care of it after that.
It seems to require a more complex patch than this, so I'd prefer to
leave it to you. (I have my hands full :))
Being 64-bit clean would be really nice, since the edk2 PCI host bridge
/ root bridge driver that OVMF uses really likes to allocate 64-bit BARs
high (unlike SeaBIOS which strives to keep everything low). Since many
devices have 64-bit capable BARs, they won't work behind PXBs (when
booting with OVMF) until this limitation is lifted.
But, as I said, I'd like to leave this to you, if you have time for it.
It is not urgent, just would be real good eventually.