Re: [kvm-unit-tests PATCH 12/32] powerpc: Fix emulator illegal instruction test for powernv

[Thomas Huth]

On 26/02/2024 11.11, Nicholas Piggin wrote:
Illegal instructions cause 0xe40 (HEAI) interrupts rather
than program interrupts.
Acked-by: Thomas Huth <th...@redhat.com>
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
  lib/powerpc/asm/processor.h |  1 +
  lib/powerpc/setup.c         | 13 +++++++++++++
  powerpc/emulator.c          | 21 ++++++++++++++++++++-
  3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/lib/powerpc/asm/processor.h b/lib/powerpc/asm/processor.h
index 9d8061962..cf1b9d8ff 100644
--- a/lib/powerpc/asm/processor.h
+++ b/lib/powerpc/asm/processor.h
@@ -11,6 +11,7 @@ void do_handle_exception(struct pt_regs *regs);
  #endif /* __ASSEMBLY__ */
  
  extern bool cpu_has_hv;
+extern bool cpu_has_heai;
  
  static inline uint64_t mfspr(int nr)
  {
diff --git a/lib/powerpc/setup.c b/lib/powerpc/setup.c
index 89e5157f2..3c81aee9e 100644
--- a/lib/powerpc/setup.c
+++ b/lib/powerpc/setup.c
@@ -87,6 +87,7 @@ static void cpu_set(int fdtnode, u64 regval, void *info)
  }
  
  bool cpu_has_hv;
+bool cpu_has_heai;
  
  static void cpu_init(void)
  {
@@ -108,6 +109,18 @@ static void cpu_init(void)
                hcall(H_SET_MODE, 0, 4, 0, 0);
  #endif
        }
+
+       switch (mfspr(SPR_PVR) & PVR_VERSION_MASK) {
+       case PVR_VER_POWER10:
+       case PVR_VER_POWER9:
+       case PVR_VER_POWER8E:
+       case PVR_VER_POWER8NVL:
+       case PVR_VER_POWER8:
+               cpu_has_heai = true;
+               break;
+       default:
+               break;
+       }
  }
  
  static void mem_init(phys_addr_t freemem_start)
diff --git a/powerpc/emulator.c b/powerpc/emulator.c
index 39dd59645..c9b17f742 100644
--- a/powerpc/emulator.c
+++ b/powerpc/emulator.c
@@ -31,6 +31,20 @@ static void program_check_handler(struct pt_regs *regs, void 
*opaque)
        regs->nip += 4;
  }
  
+static void heai_handler(struct pt_regs *regs, void *opaque)
+{
+       int *data = opaque;
+
+       if (verbose) {
+               printf("Detected invalid instruction %#018lx: %08x\n",
+                      regs->nip, *(uint32_t*)regs->nip);
+       }
+
+       *data = 8; /* Illegal instruction */
+
+       regs->nip += 4;
+}
+
  static void alignment_handler(struct pt_regs *regs, void *opaque)
  {
        int *data = opaque;
@@ -362,7 +376,12 @@ int main(int argc, char **argv)
  {
        int i;
  
-	handle_exception(0x700, program_check_handler, (void *)&is_invalid);
+       if (cpu_has_heai) {
+               handle_exception(0xe40, heai_handler, (void *)&is_invalid);
+               handle_exception(0x700, program_check_handler, (void 
*)&is_invalid);
+       } else {
+               handle_exception(0x700, program_check_handler, (void 
*)&is_invalid);

The 0x700 line looks identical to the other part of the if-statement ... I'd 
suggest to leave it outside of the if-statement, drop the else-part and just 
set 0xe40 if cpu_has_heai.

 Thomas

+       }
        handle_exception(0x600, alignment_handler, (void *)&alignment);
  
  	for (i = 1; i < argc; i++) {