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-rw-r--r--arch/powerpc/kernel/idle_book3s.S35
1 files changed, 29 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index bd739fed26e3..72dac0b58061 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -90,6 +90,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300)
* Threads will spin in HMT_LOW until the lock bit is cleared.
* r14 - pointer to core_idle_state
* r15 - used to load contents of core_idle_state
+ * r9 - used as a temporary variable
*/
core_idle_lock_held:
@@ -99,6 +100,8 @@ core_idle_lock_held:
bne 3b
HMT_MEDIUM
lwarx r15,0,r14
+ andi. r9,r15,PNV_CORE_IDLE_LOCK_BIT
+ bne core_idle_lock_held
blr
/*
@@ -163,12 +166,6 @@ _GLOBAL(pnv_powersave_common)
std r9,_MSR(r1)
std r1,PACAR1(r13)
-#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
- /* Tell KVM we're entering idle */
- li r4,KVM_HWTHREAD_IN_IDLE
- stb r4,HSTATE_HWTHREAD_STATE(r13)
-#endif
-
/*
* Go to real mode to do the nap, as required by the architecture.
* Also, we need to be in real mode before setting hwthread_state,
@@ -185,6 +182,26 @@ _GLOBAL(pnv_powersave_common)
.globl pnv_enter_arch207_idle_mode
pnv_enter_arch207_idle_mode:
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+ /* Tell KVM we're entering idle */
+ li r4,KVM_HWTHREAD_IN_IDLE
+ /******************************************************/
+ /* N O T E W E L L ! ! ! N O T E W E L L */
+ /* The following store to HSTATE_HWTHREAD_STATE(r13) */
+ /* MUST occur in real mode, i.e. with the MMU off, */
+ /* and the MMU must stay off until we clear this flag */
+ /* and test HSTATE_HWTHREAD_REQ(r13) in the system */
+ /* reset interrupt vector in exceptions-64s.S. */
+ /* The reason is that another thread can switch the */
+ /* MMU to a guest context whenever this flag is set */
+ /* to KVM_HWTHREAD_IN_IDLE, and if the MMU was on, */
+ /* that would potentially cause this thread to start */
+ /* executing instructions from guest memory in */
+ /* hypervisor mode, leading to a host crash or data */
+ /* corruption, or worse. */
+ /******************************************************/
+ stb r4,HSTATE_HWTHREAD_STATE(r13)
+#endif
stb r3,PACA_THREAD_IDLE_STATE(r13)
cmpwi cr3,r3,PNV_THREAD_SLEEP
bge cr3,2f
@@ -250,6 +267,12 @@ enter_winkle:
* r3 - requested stop state
*/
power_enter_stop:
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+ /* Tell KVM we're entering idle */
+ li r4,KVM_HWTHREAD_IN_IDLE
+ /* DO THIS IN REAL MODE! See comment above. */
+ stb r4,HSTATE_HWTHREAD_STATE(r13)
+#endif
/*
* Check if the requested state is a deep idle state.
*/