On 14/08/2019 14:33, Aravinda Prasad wrote:
On Tuesday 13 August 2019 07:47 PM, David Gibson wrote:
On Tue, Aug 13, 2019 at 01:00:24PM +0530, Aravinda Prasad wrote:
On Monday 12 August 2019 03:38 PM, David Gibson wrote:
On Mon, Aug 05, 2019 at 02:14:39PM +0530, Aravinda Prasad wrote:
Alexey/David,
With the SLOF changes, QEMU cannot resize the RTAS blob. Resizing is
required for FWNMI support which extends the RTAS blob to include an
error log upon a machine check.
The check to valid RTAS buffer fails in the guest because the rtas-size
updated in QEMU is not reflecting in the guest.
Any workaround for this?
Well, we should still be able to do it, it just means fwnmi would need
a SLOF change. It's an inconvenience, but not really a big deal.
Yes. Alexey and I were discussing about the following changes to SLOf:
diff --git a/lib/libhvcall/hvcall.S b/lib/libhvcall/hvcall.S
index b19f6dbeff2c..880d29a29122 100644
--- a/lib/libhvcall/hvcall.S
+++ b/lib/libhvcall/hvcall.S
@@ -134,6 +134,7 @@ ENTRY(hv_rtas)
ori r3,r3,KVMPPC_H_RTAS@l
HVCALL
blr
+ .space 2048
.globl hv_rtas_size
hv_rtas_size:
.long . - hv_rtas;
But this will statically reserve space for RTAS even when
SPAPR_CAP_FWNMI_MCE is OFF.
Sure. We could flag that in the DT somehow, and have SLOF reserve the
space conditionally.
Or we could just ignore it. 2 kiB is miniscule compared to our minimum
guest size, and our current RTAS is microscopic compared to PowerVM.
I also think so, 2kiB is miniscule so we can allocate it statically.
Alexey,
Can you please include the above one line fix to SLOF?
I am thinking of:
===
@@ -132,20 +132,22 @@ ENTRY(hv_rtas)
mr r4,r3
lis r3,KVMPPC_H_RTAS@h
ori r3,r3,KVMPPC_H_RTAS@l
HVCALL
blr
+ .space 2048 - (. - hv_rtas)
.globl hv_rtas_size
hv_rtas_size:
.long . - hv_rtas;
ENTRY(hv_rtas_broken_sc1)
mr r4,r3
lis r3,KVMPPC_H_RTAS@h
ori r3,r3,KVMPPC_H_RTAS@l
.long 0x7c000268
blr
+ .space 2048 - (. - hv_rtas_broken_sc1)
.globl hv_rtas_broken_sc1_size
hv_rtas_broken_sc1_size:
.long . - hv_rtas_broken_sc1;
===
to align the rtas blob to 2k precisely. But QEMU hardcoded
RTAS_ERROR_LOG_OFFSET bothers me a bit, I should probably put some sort
of a magic marker at which RTAS log can start.
David, any thoughts? The marker could be as simple as a zero, for example.
--
Alexey