[Qemu-devel] [PATCH] kvm_ppc: remove kvmppc_timer_hack

[Qemu-devel] [PATCH] kvm_ppc: remove kvmppc_timer_hack

[Paolo Bonzini]

QEMU does have an I/O thread now, that can be interrupted at any time
because the VCPU thread runs outside the iothread mutex.

Therefore, the kvmppc_timer_hack is obsolete.  Remove it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

Notes:
            Untested!

 hw/ppc/e500.c            |  4 ----
 hw/ppc/ppc440_bamboo.c   |  3 ---
 target-ppc/Makefile.objs |  2 +-
 target-ppc/kvm_ppc.c     | 41 -----------------------------------------
 target-ppc/kvm_ppc.h     |  2 --
 5 files changed, 1 insertion(+), 51 deletions(-)
 delete mode 100644 target-ppc/kvm_ppc.c

diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
index d300846..e968386 100644
--- a/hw/ppc/e500.c
+++ b/hw/ppc/e500.c
@@ -1048,10 +1048,6 @@ void ppce500_init(MachineState *machine, PPCE500Params *params)
     boot_info->entry = bios_entry;
     boot_info->dt_base = dt_base;
     boot_info->dt_size = dt_size;
-
-    if (kvm_enabled()) {
-        kvmppc_init();
-    }
 }
 
 static int e500_ccsr_initfn(SysBusDevice *dev)
diff --git a/hw/ppc/ppc440_bamboo.c b/hw/ppc/ppc440_bamboo.c
index 032fa80..5745f03 100644
--- a/hw/ppc/ppc440_bamboo.c
+++ b/hw/ppc/ppc440_bamboo.c
@@ -288,9 +288,6 @@ static void bamboo_init(MachineState *machine)
             exit(1);
         }
     }
-
-    if (kvm_enabled())
-        kvmppc_init();
 }
 
 static QEMUMachine bamboo_machine = {
diff --git a/target-ppc/Makefile.objs b/target-ppc/Makefile.objs
index a7ae392..0a96ee2 100644
--- a/target-ppc/Makefile.objs
+++ b/target-ppc/Makefile.objs
@@ -4,7 +4,7 @@ ifeq ($(CONFIG_SOFTMMU),y)
 obj-y += machine.o mmu_helper.o mmu-hash32.o
 obj-$(TARGET_PPC64) += mmu-hash64.o arch_dump.o
 endif
-obj-$(CONFIG_KVM) += kvm.o kvm_ppc.o
+obj-$(CONFIG_KVM) += kvm.o
 obj-$(call lnot,$(CONFIG_KVM)) += kvm-stub.o
 obj-y += dfp_helper.o
 obj-y += excp_helper.o
diff --git a/target-ppc/kvm_ppc.c b/target-ppc/kvm_ppc.c
deleted file mode 100644
index f769acd..0000000
--- a/target-ppc/kvm_ppc.c
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * PowerPC KVM support
- *
- * Copyright IBM Corp. 2008
- *
- * Authors:
- *  Hollis Blanchard <hollisb@us.ibm.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2 or later.
- * See the COPYING file in the top-level directory.
- *
- */
-
-#include "qemu-common.h"
-#include "qemu/timer.h"
-#include "kvm_ppc.h"
-#include "sysemu/device_tree.h"
-#include "qemu/main-loop.h"
-
-#define PROC_DEVTREE_PATH "/proc/device-tree"
-
-static QEMUTimer *kvmppc_timer;
-static unsigned int kvmppc_timer_rate;
-
-static void kvmppc_timer_hack(void *opaque)
-{
-    qemu_notify_event();
-    timer_mod(kvmppc_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + kvmppc_timer_rate);
-}
-
-void kvmppc_init(void)
-{
-    /* XXX The only reason KVM yields control back to qemu is device IO. Since
-     * an idle guest does no IO, qemu's device model will never get a chance to
-     * run. So, until QEMU gains IO threads, we create this timer to ensure
-     * that the device model gets a chance to run. */
-    kvmppc_timer_rate = get_ticks_per_sec() / 10;
-    kvmppc_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &kvmppc_timer_hack, NULL);
-    timer_mod(kvmppc_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + kvmppc_timer_rate);
-}
-
diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
index 4d30e27..5c1d334 100644
--- a/target-ppc/kvm_ppc.h
+++ b/target-ppc/kvm_ppc.h
@@ -11,8 +11,6 @@
 
 #define TYPE_HOST_POWERPC_CPU "host-" TYPE_POWERPC_CPU
 
-void kvmppc_init(void);
-
 #ifdef CONFIG_KVM
 
 uint32_t kvmppc_get_tbfreq(void);
-- 
2.4.3

Re: [Qemu-devel] [PATCH] kvm_ppc: remove kvmppc_timer_hack

[Alexander Graf]

On 27.07.15 13:46, Paolo Bonzini wrote:
> QEMU does have an I/O thread now, that can be interrupted at any time
> because the VCPU thread runs outside the iothread mutex.
> 
> Therefore, the kvmppc_timer_hack is obsolete.  Remove it.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Thanks, applied to ppc-next-2.5. I think all bugs we had that made this
hack necessary have long been fixed, so removing the hack is definitely
overdue.


Alex