On 05/23/2013 08:42:21 PM, Paul Mackerras wrote:
This adds the remaining two hypercalls defined by PAPR for
manipulating
the XICS interrupt controller, H_IPOLL and H_XIRR_X. H_IPOLL returns
information about the priority and pending interrupts for a virtual
cpu, without changing any state. H_XIRR_X is like H_XIRR in that it
reads and acknowledges the highest-priority pending interrupt, but it
also returns the timestamp (timebase register value) from when the
interrupt was first received by the hypervisor. Currently we just
return the current time, since we don't do any software queueing of
virtual interrupts inside the XICS emulation code.
These hcalls are not currently used by Linux guests, but may be in
future.
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxx>
---
Unfortunately I missed these two hcalls in the previous submissions.
It would be good to get this patch into 3.10 so we don't have a
kernel version with these calls missing from the API, in case future
guest kernels want to use them.
Alex, given you're on vacation at the moment, are you OK with Ben
taking this through his tree?
I believe Alex is staying far away from e-mail on his vacation. He's
asked me to fill in for him while he's gone.
The patch itself seems reasonable (though I don't know much about XICS,
and do have one question...), but I'll leave it up to Gleb/Marcelo/Ben
if it should go in for 3.10 and via which tree. I understand the
desire to not have an incomplete ABI in a released version, but Linus
is already grumbling about how much went into rc3, and you say the
hcalls aren't currently used... Are they likely to be used in any
timeframe in which we'd reasonably care about 3.10? If so, would the
effect of not having them implemented be such that it would be worse
than not having in-kernel XICS at all?
@@ -787,6 +804,18 @@ int kvmppc_xics_hcall(struct kvm_vcpu *vcpu, u32
req)
if (!xics || !vcpu->arch.icp)
return H_HARDWARE;
+ /* These requests don't have real-mode implementations at
present */
+ switch (req) {
+ case H_XIRR_X:
+ res = kvmppc_h_xirr(vcpu);
+ kvmppc_set_gpr(vcpu, 4, res);
+ kvmppc_set_gpr(vcpu, 5, get_tb());
+ return rc;
+ case H_IPOLL:
+ rc = kvmppc_h_ipoll(vcpu, kvmppc_get_gpr(vcpu, 4));
+ return rc;
+ }
+
/* Check for real mode returning too hard */
if (xics->real_mode)
return kvmppc_xics_rm_complete(vcpu, req);
Could you explain what's going on here relative to
kvmppc_xics_rm_complete()? What does "returning too hard" mean, and
why must rm_action not be checked for these hcalls?
-Scott
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