[PULL,01/59] hvf: arm: Ignore writes to CNTP_CTL_EL0

Commit Message

Philippe Mathieu-Daudé Dec. 20, 2024, 4:14 p.m. UTC

From: Alexander Graf <[e-mail]>

MacOS unconditionally disables interrupts of the physical timer on boot
and then continues to use the virtual one. We don't really want to support
a full physical timer emulation, so let's just ignore those writes.

Signed-off-by: Alexander Graf <[e-mail]>
Signed-off-by: Phil Dennis-Jordan <[e-mail]>
Reviewed-by: Akihiko Odaki <[e-mail]>
Message-ID: <[e-mail]>
Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 target/arm/hvf/hvf.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Patch

diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index ca7ea92774a..d75e504dcda 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -11,6 +11,7 @@ 
 
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
+#include "qemu/log.h"
 
 #include "sysemu/runstate.h"
 #include "sysemu/hvf.h"
@@ -184,6 +185,7 @@  void hvf_arm_init_debug(void)
 #define SYSREG_OSLSR_EL1      SYSREG(2, 0, 1, 1, 4)
 #define SYSREG_OSDLR_EL1      SYSREG(2, 0, 1, 3, 4)
 #define SYSREG_CNTPCT_EL0     SYSREG(3, 3, 14, 0, 1)
+#define SYSREG_CNTP_CTL_EL0   SYSREG(3, 3, 14, 2, 1)
 #define SYSREG_PMCR_EL0       SYSREG(3, 3, 9, 12, 0)
 #define SYSREG_PMUSERENR_EL0  SYSREG(3, 3, 9, 14, 0)
 #define SYSREG_PMCNTENSET_EL0 SYSREG(3, 3, 9, 12, 1)
@@ -1620,6 +1622,13 @@  static int hvf_sysreg_write(CPUState *cpu, uint32_t reg, uint64_t val)
     case SYSREG_OSLAR_EL1:
         env->cp15.oslsr_el1 = val & 1;
         return 0;
+    case SYSREG_CNTP_CTL_EL0:
+        /*
+         * Guests should not rely on the physical counter, but macOS emits
+         * disable writes to it. Let it do so, but ignore the requests.
+         */
+        qemu_log_mask(LOG_UNIMP, "Unsupported write to CNTP_CTL_EL0\n");
+        return 0;
     case SYSREG_OSDLR_EL1:
         /* Dummy register */
         return 0;