From: Simon Guo <wei.guo.simon@xxxxxxxxx>
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).
Signed-off-by: Simon Guo <wei.guo.simon@xxxxxxxxx>
---
arch/powerpc/include/asm/kvm_book3s.h | 2 ++
arch/powerpc/kvm/book3s_emulate.c | 4 ++++
arch/powerpc/kvm/book3s_pr.c | 21 ++++++++++++++++-----
arch/powerpc/kvm/tm.S | 16 ++++++++++++++--
4 files changed, 36 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 5873906..4148a3d 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -267,6 +267,8 @@ static inline void kvmppc_save_tm_sprs(struct kvm_vcpu *vcpu) {}
static inline void kvmppc_restore_tm_sprs(struct kvm_vcpu *vcpu) {}
#endif
+void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac);
+
extern int kvm_irq_bypass;
static inline struct kvmppc_vcpu_book3s *to_book3s(struct kvm_vcpu *vcpu)
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index 6c5ef8c..8fd3af6a 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -173,6 +173,9 @@ static void kvmppc_emulate_treclaim(struct kvm_vcpu *vcpu, int ra_val)
guest_msr &= ~(MSR_TS_MASK);
kvmppc_set_msr(vcpu, guest_msr);
preempt_enable();
+
+ if (vcpu->arch.shadow_fscr & FSCR_TAR)
+ mtspr(SPRN_TAR, vcpu->arch.tar);
}
static void kvmppc_emulate_trchkpt(struct kvm_vcpu *vcpu)
@@ -185,6 +188,7 @@ static void kvmppc_emulate_trchkpt(struct kvm_vcpu *vcpu)
* copy.
*/
kvmppc_giveup_ext(vcpu, MSR_VSX);
+ kvmppc_giveup_fac(vcpu, FSCR_TAR_LG);
kvmppc_copyto_vcpu_tm(vcpu);
kvmppc_save_tm_sprs(vcpu);
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 29ec92e..19f9934 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -55,7 +55,7 @@
static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
ulong msr);
-static void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac);
+static int kvmppc_handle_fac(struct kvm_vcpu *vcpu, ulong fac);
/* Some compatibility defines */
#ifdef CONFIG_PPC_BOOK3S_32
@@ -348,6 +348,7 @@ void kvmppc_save_tm_pr(struct kvm_vcpu *vcpu)
return;
}
+ kvmppc_giveup_fac(vcpu, FSCR_TAR_LG);
kvmppc_giveup_ext(vcpu, MSR_VSX);
preempt_disable();
@@ -359,8 +360,11 @@ void kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu)
{
if (!MSR_TM_ACTIVE(kvmppc_get_msr(vcpu))) {
kvmppc_restore_tm_sprs(vcpu);
- if (kvmppc_get_msr(vcpu) & MSR_TM)
+ if (kvmppc_get_msr(vcpu) & MSR_TM) {
kvmppc_handle_lost_math_exts(vcpu);
+ if (vcpu->arch.fscr & FSCR_TAR)
+ kvmppc_handle_fac(vcpu, FSCR_TAR_LG);
+ }
return;
}
@@ -368,9 +372,11 @@ void kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu)
_kvmppc_restore_tm_pr(vcpu, kvmppc_get_msr(vcpu));
preempt_enable();
- if (kvmppc_get_msr(vcpu) & MSR_TM)
+ if (kvmppc_get_msr(vcpu) & MSR_TM) {
kvmppc_handle_lost_math_exts(vcpu);
-
+ if (vcpu->arch.fscr & FSCR_TAR)
+ kvmppc_handle_fac(vcpu, FSCR_TAR_LG);
+ }
}
#endif
@@ -828,7 +834,7 @@ void kvmppc_giveup_ext(struct kvm_vcpu *vcpu, ulong msr)
}
/* Give up facility (TAR / EBB / DSCR) */
-static void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac)
+void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac)
{
#ifdef CONFIG_PPC_BOOK3S_64
if (!(vcpu->arch.shadow_fscr & (1ULL << fac))) {
@@ -1029,7 +1035,12 @@ void kvmppc_set_fscr(struct kvm_vcpu *vcpu, u64 fscr)
if ((vcpu->arch.fscr & FSCR_TAR) && !(fscr & FSCR_TAR)) {
/* TAR got dropped, drop it in shadow too */
kvmppc_giveup_fac(vcpu, FSCR_TAR_LG);
+ } else if (!(vcpu->arch.fscr & FSCR_TAR) && (fscr & FSCR_TAR)) {
+ vcpu->arch.fscr = fscr;
+ kvmppc_handle_fac(vcpu, FSCR_TAR_LG);
+ return;
}
+
vcpu->arch.fscr = fscr;
}
#endif
diff --git a/arch/powerpc/kvm/tm.S b/arch/powerpc/kvm/tm.S
index 269dd11..aa84e4a 100644
--- a/arch/powerpc/kvm/tm.S
+++ b/arch/powerpc/kvm/tm.S
@@ -164,15 +164,21 @@ _GLOBAL(_kvmppc_save_tm_pr)
mfmsr r5
SAVE_GPR(5, r1)
- /* also save DSCR/CR so that it can be recovered later */
+ /* also save DSCR/CR/TAR so that it can be recovered later */
mfspr r6, SPRN_DSCR
SAVE_GPR(6, r1)
mfcr r7
stw r7, _CCR(r1)
+ mfspr r8, SPRN_TAR
+ SAVE_GPR(8, r1)
+
bl __kvmppc_save_tm
+ REST_GPR(8, r1)
+ mtspr SPRN_TAR, r8
+
ld r7, _CCR(r1)
mtcr r7
@@ -335,15 +341,21 @@ _GLOBAL(_kvmppc_restore_tm_pr)
mfmsr r5
SAVE_GPR(5, r1)
- /* also save DSCR/CR so that it can be recovered later */
+ /* also save DSCR/CR/TAR so that it can be recovered later */
mfspr r6, SPRN_DSCR
SAVE_GPR(6, r1)
mfcr r7
stw r7, _CCR(r1)
+ mfspr r8, SPRN_TAR
+ SAVE_GPR(8, r1)
+
bl __kvmppc_restore_tm
+ REST_GPR(8, r1)
+ mtspr SPRN_TAR, r8
+
ld r7, _CCR(r1)
mtcr r7
--
1.8.3.1
