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-rw-r--r--arch/powerpc/kvm/book3s_hv_rmhandlers.S30
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index faebcbb8c4db..0496e66aaa56 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -11,6 +11,7 @@
*/
#include <asm/ppc_asm.h>
+#include <asm/code-patching-asm.h>
#include <asm/kvm_asm.h>
#include <asm/reg.h>
#include <asm/mmu.h>
@@ -1487,6 +1488,13 @@ guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */
1:
#endif /* CONFIG_KVM_XICS */
+ /*
+ * Possibly flush the link stack here, before we do a blr in
+ * guest_exit_short_path.
+ */
+1: nop
+ patch_site 1b patch__call_kvm_flush_link_stack
+
/* If we came in through the P9 short path, go back out to C now */
lwz r0, STACK_SLOT_SHORT_PATH(r1)
cmpwi r0, 0
@@ -1963,6 +1971,28 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
mtlr r0
blr
+.balign 32
+.global kvm_flush_link_stack
+kvm_flush_link_stack:
+ /* Save LR into r0 */
+ mflr r0
+
+ /* Flush the link stack. On Power8 it's up to 32 entries in size. */
+ .rept 32
+ bl .+4
+ .endr
+
+ /* And on Power9 it's up to 64. */
+BEGIN_FTR_SECTION
+ .rept 32
+ bl .+4
+ .endr
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
+
+ /* Restore LR */
+ mtlr r0
+ blr
+
kvmppc_guest_external:
/* External interrupt, first check for host_ipi. If this is
* set, we know the host wants us out so let's do it now