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authorNicholas Piggin <npiggin@gmail.com>2021-07-12 04:36:50 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2021-07-15 14:53:37 +0300
commite44fbdb68049539de9923ce4bad2d277aef54892 (patch)
treeb5df1f342f7f20f3be8d893210ec49b6d2401b20 /arch/powerpc/kvm/book3s_hv_p9_entry.c
parente73f0f0ee7541171d89f2e2491130c7771ba58d3 (diff)
downloadlinux-e44fbdb68049539de9923ce4bad2d277aef54892.tar.xz
KVM: PPC: Book3S HV P9: Fix guest TM support
The conversion to C introduced several bugs in TM handling that can cause host crashes with TM bad thing interrupts. Mostly just simple typos or missed logic in the conversion that got through due to my not testing TM in the guest sufficiently. - Early TM emulation for the softpatch interrupt should be done if fake suspend mode is _not_ active. - Early TM emulation wants to return immediately to the guest so as to not doom transactions unnecessarily. - And if exiting from the guest, the host MSR should include the TM[S] bit if the guest was T/S, before it is treclaimed. After this fix, all the TM selftests pass when running on a P9 processor that implements TM with softpatch interrupt. Fixes: 89d35b2391015 ("KVM: PPC: Book3S HV P9: Implement the rest of the P9 path in C") Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210712013650.376325-1-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_p9_entry.c')
-rw-r--r--arch/powerpc/kvm/book3s_hv_p9_entry.c25
1 files changed, 22 insertions, 3 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c
index 83f592eadcd2..961b3d70483c 100644
--- a/arch/powerpc/kvm/book3s_hv_p9_entry.c
+++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c
@@ -317,6 +317,9 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
*/
mtspr(SPRN_HDEC, hdec);
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+tm_return_to_guest:
+#endif
mtspr(SPRN_DAR, vcpu->arch.shregs.dar);
mtspr(SPRN_DSISR, vcpu->arch.shregs.dsisr);
mtspr(SPRN_SRR0, vcpu->arch.shregs.srr0);
@@ -415,11 +418,23 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
* is in real suspend mode and is trying to transition to
* transactional mode.
*/
- if (local_paca->kvm_hstate.fake_suspend &&
+ if (!local_paca->kvm_hstate.fake_suspend &&
(vcpu->arch.shregs.msr & MSR_TS_S)) {
if (kvmhv_p9_tm_emulation_early(vcpu)) {
- /* Prevent it being handled again. */
- trap = 0;
+ /*
+ * Go straight back into the guest with the
+ * new NIP/MSR as set by TM emulation.
+ */
+ mtspr(SPRN_HSRR0, vcpu->arch.regs.nip);
+ mtspr(SPRN_HSRR1, vcpu->arch.shregs.msr);
+
+ /*
+ * tm_return_to_guest re-loads SRR0/1, DAR,
+ * DSISR after RI is cleared, in case they had
+ * been clobbered by a MCE.
+ */
+ __mtmsrd(0, 1); /* clear RI */
+ goto tm_return_to_guest;
}
}
#endif
@@ -499,6 +514,10 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc
* If we are in real mode, only switch MMU on after the MMU is
* switched to host, to avoid the P9_RADIX_PREFETCH_BUG.
*/
+ if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) &&
+ vcpu->arch.shregs.msr & MSR_TS_MASK)
+ msr |= MSR_TS_S;
+
__mtmsrd(msr, 0);
end_timing(vcpu);