Changeset 106373 in vbox for trunk/src/VBox/VMM/VMMR3

Timestamp:

Oct 16, 2024 1:38:57 PM (3 months ago)

Author:

vboxsync

Message:

VMM/NEMR3Native-darwin-armv8.cpp: Crude workaround for getting Windows/ARM booting as a guest because it assumes a working PMU which AppleSilicon hardware doesn't support, bugref:10732

File:

• trunk/src/VBox/VMM/VMMR3/NEMR3Native-darwin-armv8.cpp (modified) (1 diff)

trunk/src/VBox/VMM/VMMR3/NEMR3Native-darwin-armv8.cpp

@@ -1731 +1731 @@
     {
         RT_NOREF(pVM);
-        rcStrict = CPUMQueryGuestSysReg(pVCpu, idSysReg, &u64Val);
+
+        /** @todo Windows assumes a working PMU which is not available on AppleSilicon. It uses it
+         * to determine the base frequency it seems (because without the * 100 multiplier the frequency
+         * is detetcted as 24MHz. This needs to be moved into a separate PMU emulation (to be created) for
+         * all backends to share (Linux/KVM when running on AppleSilicon hardware). */
+        if (   idSysReg == ARMV8_AARCH64_SYSREG_PMCR_EL0
+            || idSysReg == ARMV8_AARCH64_SYSREG_PMCCNTR_EL0)
+        {
+            if (idSysReg == ARMV8_AARCH64_SYSREG_PMCCNTR_EL0)
+            {
+                u64Val = ASMReadTSC() * 100;
+            }
+            else
+                u64Val = 0;
+        }
+        else
+            rcStrict = CPUMQueryGuestSysReg(pVCpu, idSysReg, &u64Val);
         Log4(("SysInsnExit/%u: %08RX64: READ %u:%u:%u:%u:%u -> %#RX64 rcStrict=%Rrc\n",
               pVCpu->idCpu, pVCpu->cpum.GstCtx.Pc.u64, uOp0, uOp1, uCRn, uCRm, uOp2, u64Val,