[Minios-devel] [UNIKRAFT PATCH 03/23] plat: Hardware context - Use interrupt stack when handling interrupts

[Costin Lupu <costin.lupu@xxxxxxxxx>]

Now that we use a special "stack" for saving the thread registers when entering
interrupt context, we have to get back to using the interrupt stack for the
rest of job.

Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
---
 plat/kvm/x86/cpu_vectors_x86_64.S | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/plat/kvm/x86/cpu_vectors_x86_64.S 
b/plat/kvm/x86/cpu_vectors_x86_64.S
index 1af2fd00..41bd6f88 100644
--- a/plat/kvm/x86/cpu_vectors_x86_64.S
+++ b/plat/kvm/x86/cpu_vectors_x86_64.S
@@ -24,6 +24,8 @@
  */
 /* Taken from solo5 */
 
+#include <uk/config.h>
+#include <uk/arch/limits.h>
 #include <x86/traps.h>
 #include <x86/regs.h>
 
@@ -92,11 +94,28 @@ ENTRY(cpu_irq_\irqno)
 
        pushq $0                            /* no error code */
        PUSH_CALLER_SAVE
+#if CONFIG_HAVE_SCHED_PREEMPT
+       pushq $1f                           /* save continuation */
+       /* Set kernel stack */
+       movq intr_stack_start(%rip), %rsp
+#else
        subq $REGS_PAD_SIZE, %rsp           /* we have some padding */
 
+#endif /* CONFIG_HAVE_SCHED_PREEMPT */
+
        movq $\irqno, %rdi
        call _ukplat_irq_handle
 
+#if CONFIG_HAVE_SCHED_PREEMPT
+1:
+       /* Load current thread */
+       and $STACK_MASK_TOP, %rsp
+       mov (%rsp), %rsp
+       /* Load thread exception stack */
+       mov OFFSETOF_UKTHREAD_REGS(%rsp), %rsp
+       mov (%rsp), %rsp
+#endif
+
        addq $REGS_PAD_SIZE, %rsp           /* we have some padding */
        POP_CALLER_SAVE
        addq $8, %rsp
@@ -104,6 +123,11 @@ ENTRY(cpu_irq_\irqno)
        iretq
 .endm
 
+#if CONFIG_HAVE_SCHED_PREEMPT
+intr_stack_start:
+       .quad cpu_intr_stack + __STACK_SIZE - 8
+#endif
+
 TRAP_ENTRY divide_error,     0
 TRAP_ENTRY debug,            0
 TRAP_ENTRY nmi,              0
-- 
2.20.1


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