Re: [PATCH v3 24/29] KVM: PPC: Book3S PR: Support TAR handling for PR KVM HTM.

Hi Paul,
On Tue, May 22, 2018 at 09:44:47PM +1000, Paul Mackerras wrote:

On Mon, May 21, 2018 at 12:09:41PM +0800, wei.guo.simon@gmail.com wrote:

quoted

From: Simon Guo <redacted>

Currently guest kernel doesn't handle TAR fac unavailable and it always
runs with TAR bit on. PR KVM will lazily enable TAR. TAR is not a
frequent-use reg and it is not included in SVCPU struct.

Due to the above, the checkpointed TAR val might be a bogus TAR val.
To solve this issue, we will make vcpu->arch.fscr tar bit consistent
with shadow_fscr when TM enabled.

At the end of emulating treclaim., the correct TAR val need to be loaded
into reg if FSCR_TAR bit is on.
At the beginning of emulating trechkpt., TAR needs to be flushed so that
the right tar val can be copy into tar_tm.

Tested with:
tools/testing/selftests/powerpc/tm/tm-tar
tools/testing/selftests/powerpc/ptrace/ptrace-tm-tar (remove DSCR/PPR
related testing).

With this patch, a 32-bit powermac compile with PR KVM enabled gives
this error:

arch/powerpc/kvm/book3s_pr.c:58:12: error: ‘kvmppc_handle_fac’ declared ‘static’ but never defined [-Werror=unused-function]
 static int kvmppc_handle_fac(struct kvm_vcpu *vcpu, ulong fac);
            ^
cc1: all warnings being treated as errors
scripts/Makefile.build:312: recipe for target 'arch/powerpc/kvm/book3s_pr.o' failed

The easy fix is a #ifdef CONFIG_PPC_BOOK3S_64 around the forward
static definition.

Thx for find that. I will fix that and send V4 includes that simple fix.

BR,
- Simon