From d3adadf4cfedca2a165cf0aefbe05f377cd9bad1 Mon Sep 17 00:00:00 2001
From: Christian Prochaska <christian.prochaska@genode-labs.com>
Date: Mon, 17 Jan 2022 09:23:25 +0100
Subject: [PATCH] virtualbox6: adapt watchdog timer interval dynamically

Issue #4381
---
 repos/ports/ports/virtualbox6.hash            |  2 +-
 repos/ports/src/virtualbox6/nem.cc            | 26 +++++++++
 .../src/virtualbox6/patches/rttimer.patch     | 54 +++++++++++++++++++
 repos/ports/src/virtualbox6/patches/series    |  1 +
 4 files changed, 82 insertions(+), 1 deletion(-)
 create mode 100644 repos/ports/src/virtualbox6/patches/rttimer.patch

diff --git a/repos/ports/ports/virtualbox6.hash b/repos/ports/ports/virtualbox6.hash
index e01ed08739..d4c61036b9 100644
--- a/repos/ports/ports/virtualbox6.hash
+++ b/repos/ports/ports/virtualbox6.hash
@@ -1 +1 @@
-4520096005074d88433410752e88df1e748a80dd
+7991a9853bb0a96cad9a54ebaf3290dfda9ae2d2
diff --git a/repos/ports/src/virtualbox6/nem.cc b/repos/ports/src/virtualbox6/nem.cc
index 466f17d08d..d9a1b3de0a 100644
--- a/repos/ports/src/virtualbox6/nem.cc
+++ b/repos/ports/src/virtualbox6/nem.cc
@@ -14,9 +14,11 @@
 
 /* VirtualBox includes */
 #include <VBox/vmm/cpum.h>      /* must be included before CPUMInternal.h */
+#include <VBox/vmm/tm.h>        /* must be included before TMInternal.h */
 #define VMCPU_INCL_CPUM_GST_CTX /* needed for cpum.GstCtx */
 #include <CPUMInternal.h>       /* enable access to cpum.s.* */
 #include <HMInternal.h>         /* enable access to hm.s.* */
+#include <TMInternal.h>         /* enable access to tm.s.* */
 #define RT_OS_WINDOWS           /* needed for definition all nem.s members */
 #include <NEMInternal.h>        /* enable access to nem.s.* */
 #undef RT_OS_WINDOWS
@@ -253,6 +255,30 @@ VBOXSTRICTRC nemR3NativeRunGC(PVM pVM, PVMCPU pVCpu)
 {
 	using namespace Sup;
 
+	/*
+	 * Program the watchdog timer near the next expiring virtual sync timeout.
+	 * Without this code the watchdog timer would be programmed to a fixed
+	 * interval (10ms by default), which could be too high or cause too much
+	 * CPU load if set lower. Other hosts use the VMX preemption timer, which
+	 * is currently not available on Genode.
+	 */
+	{
+		static ::uint64_t current_interval_ns { 0 };
+		static Mutex interval_mutex { };
+
+		Mutex::Guard guard(interval_mutex);
+
+		::uint64_t new_interval_ns = TMVirtualSyncGetNsToDeadline(pVM);
+		new_interval_ns = (new_interval_ns / RT_NS_1MS) * RT_NS_1MS;
+		new_interval_ns = max(new_interval_ns, 1 * RT_NS_1MS);
+		new_interval_ns = min(new_interval_ns, 10 * RT_NS_1MS);
+
+		if (new_interval_ns != current_interval_ns) {
+			RTTimerChangeInterval(pVM->tm.s.pTimer, new_interval_ns);
+			current_interval_ns = new_interval_ns;
+		}
+	}
+
 	Vm &vm = *static_cast<Vm *>(pVM);
 
 	/* commit on VM entry */
diff --git a/repos/ports/src/virtualbox6/patches/rttimer.patch b/repos/ports/src/virtualbox6/patches/rttimer.patch
new file mode 100644
index 0000000000..d05308f749
--- /dev/null
+++ b/repos/ports/src/virtualbox6/patches/rttimer.patch
@@ -0,0 +1,54 @@
+Implement RTTimerChangeInterval()
+
+diff --git a/src/virtualbox6/src/VBox/Runtime/generic/timer-generic.cpp b/src/virtualbox6/src/VBox/Runtime/generic/timer-generic.cpp
+index 6857bfb..7a32560 100644
+--- a/src/virtualbox6/src/VBox/Runtime/generic/timer-generic.cpp
++++ b/src/virtualbox6/src/VBox/Runtime/generic/timer-generic.cpp
+@@ -223,10 +223,45 @@ RT_EXPORT_SYMBOL(RTTimerStop);
+ 
+ RTDECL(int) RTTimerChangeInterval(PRTTIMER pTimer, uint64_t u64NanoInterval)
+ {
++    /* implementation ported from timerlr-generic.cpp for Genode */
++
+     if (!rtTimerIsValid(pTimer))
+         return VERR_INVALID_HANDLE;
+-    NOREF(u64NanoInterval);
+-    return VERR_NOT_SUPPORTED;
++
++    PRTTIMER pThis = pTimer;
++
++    /*
++     * Do the job accoring to state and caller.
++     */
++    int rc;
++    if (pThis->fSuspended)
++    {
++        /* Stopped: Just update the interval. */
++        ASMAtomicWriteU64(&pThis->u64NanoInterval, u64NanoInterval);
++        rc = VINF_SUCCESS;
++    }
++    else if (RTThreadSelf() == pThis->Thread)
++    {
++        /* Running: Updating interval from the callback. */
++        uint64_t u64Now = RTTimeNanoTS();
++        pThis->iTick           = 0;
++        pThis->u64StartTS      = u64Now;
++        pThis->u64NextTS       = u64Now;
++        ASMAtomicWriteU64(&pThis->u64NanoInterval, u64NanoInterval);
++        rc = VINF_SUCCESS;
++    }
++    else
++    {
++        /* Running: Stopping  */
++        rc = RTTimerStop(pThis);
++        if (RT_SUCCESS(rc))
++        {
++            ASMAtomicWriteU64(&pThis->u64NanoInterval, u64NanoInterval);
++            rc = RTTimerStart(pThis, 0);
++        }
++    }
++
++    return rc;
+ }
+ RT_EXPORT_SYMBOL(RTTimerChangeInterval);
+ 
diff --git a/repos/ports/src/virtualbox6/patches/series b/repos/ports/src/virtualbox6/patches/series
index c813ae53c0..a4c29a49c2 100644
--- a/repos/ports/src/virtualbox6/patches/series
+++ b/repos/ports/src/virtualbox6/patches/series
@@ -7,3 +7,4 @@ devahci.patch
 smp_sipi.patch
 tm_poke.patch
 exec_state.patch
+rttimer.patch