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[Qemu-devel] [PATCH 05/17] ppc: Fix hreg_store_msr() so that non-HV mode
From: |
Cédric Le Goater |
Subject: |
[Qemu-devel] [PATCH 05/17] ppc: Fix hreg_store_msr() so that non-HV mode cannot alter MSR:HV |
Date: |
Mon, 14 Mar 2016 17:56:28 +0100 |
From: Benjamin Herrenschmidt <address@hidden>
This helper is only used by the various instructions that can alter
MSR and not interrupts. Add a comment to that effect to the interrupt
code as well in case somebody wants to change this
Signed-off-by: Benjamin Herrenschmidt <address@hidden>
Reviewed-by: David Gibson <address@hidden>
---
target-ppc/excp_helper.c | 8 ++++++--
target-ppc/helper_regs.h | 4 ++--
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c
index c890853d861b..37d4721db63b 100644
--- a/target-ppc/excp_helper.c
+++ b/target-ppc/excp_helper.c
@@ -666,8 +666,12 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int
excp_model, int excp)
}
}
#endif
- /* XXX: we don't use hreg_store_msr here as already have treated
- * any special case that could occur. Just store MSR and update hflags
+ /* We don't use hreg_store_msr here as already have treated
+ * any special case that could occur. Just store MSR and update hflags
+ *
+ * Note: We *MUST* not use hreg_store_msr() as-is anyway because it
+ * will prevent setting of the HV bit which some exceptions might need
+ * to do.
*/
env->msr = new_msr & env->msr_mask;
hreg_compute_hflags(env);
diff --git a/target-ppc/helper_regs.h b/target-ppc/helper_regs.h
index 271fddf17f0a..844240d1a755 100644
--- a/target-ppc/helper_regs.h
+++ b/target-ppc/helper_regs.h
@@ -75,8 +75,8 @@ static inline int hreg_store_msr(CPUPPCState *env,
target_ulong value,
excp = 0;
value &= env->msr_mask;
#if !defined(CONFIG_USER_ONLY)
- if (!alter_hv) {
- /* mtmsr cannot alter the hypervisor state */
+ /* Neither mtmsr nor guest state can alter HV */
+ if (!alter_hv || !(env->msr & MSR_HVB)) {
value &= ~MSR_HVB;
value |= env->msr & MSR_HVB;
}
--
2.1.4
- [Qemu-devel] [PATCH 02/17] ppc: Add macros to register hypervisor mode SPRs, (continued)
[Qemu-devel] [PATCH 05/17] ppc: Fix hreg_store_msr() so that non-HV mode cannot alter MSR:HV,
Cédric Le Goater <=
[Qemu-devel] [PATCH 16/17] ppc: Add dummy CIABR SPR, Cédric Le Goater, 2016/03/14
[Qemu-devel] [PATCH 08/17] ppc: Add placeholder SPRs for DPDES and DHDES on P8, Cédric Le Goater, 2016/03/14