From 82a93a1d307064f35c363f79b04b0a0149ac53d9 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Mon, 3 Jul 2017 20:20:53 +1000 Subject: spapr: Remove 'awaiting_allocation' DRC flag The awaiting_allocation flag in the DRC was introduced by aab9913 "spapr_drc: Prevent detach racing against attach for CPU DR", allegedly to prevent a guest crash on racing attach and detach. Except.. information from the BZ actually suggests a qemu crash, not a guest crash. And there shouldn't be a problem here anyway: if the guest has already moved the DRC away from UNUSABLE state, the detach would already be deferred, and if it hadn't it should be safe to detach it (the guest should fail gracefully when it attempts to change the allocation state). I think this was probably just a bandaid for some other problem in the state management. So, remove awaiting_allocation and associated code. Signed-off-by: David Gibson Reviewed-by: Laurent Vivier Reviewed-by: Greg Kurz Tested-by: Greg Kurz Tested-by: Daniel Barboza --- hw/ppc/spapr_drc.c | 25 +++---------------------- 1 file changed, 3 insertions(+), 22 deletions(-) (limited to 'hw') diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c index 31181dab1d..7f872a4803 100644 --- a/hw/ppc/spapr_drc.c +++ b/hw/ppc/spapr_drc.c @@ -170,19 +170,13 @@ static uint32_t drc_set_usable(sPAPRDRConnector *drc) if (!drc->dev) { return RTAS_OUT_NO_SUCH_INDICATOR; } - if (drc->awaiting_release && drc->awaiting_allocation) { - /* kernel is acknowledging a previous hotplug event - * while we are already removing it. - * it's safe to ignore awaiting_allocation here since we know the - * situation is predicated on the guest either already having done - * so (boot-time hotplug), or never being able to acquire in the - * first place (hotplug followed by immediate unplug). - */ + if (drc->awaiting_release) { + /* Don't allow the guest to move a device away from UNUSABLE + * state when we want to unplug it */ return RTAS_OUT_NO_SUCH_INDICATOR; } drc->allocation_state = SPAPR_DR_ALLOCATION_STATE_USABLE; - drc->awaiting_allocation = false; return RTAS_OUT_SUCCESS; } @@ -357,10 +351,6 @@ void spapr_drc_attach(sPAPRDRConnector *drc, DeviceState *d, void *fdt, drc->fdt = fdt; drc->fdt_start_offset = fdt_start_offset; - if (spapr_drc_type(drc) != SPAPR_DR_CONNECTOR_TYPE_PCI) { - drc->awaiting_allocation = true; - } - object_property_add_link(OBJECT(drc), "device", object_get_typename(OBJECT(drc->dev)), (Object **)(&drc->dev), @@ -398,12 +388,6 @@ void spapr_drc_detach(sPAPRDRConnector *drc, DeviceState *d, Error **errp) return; } - if (drc->awaiting_allocation) { - drc->awaiting_release = true; - trace_spapr_drc_awaiting_allocation(spapr_drc_index(drc)); - return; - } - spapr_drc_release(drc); } @@ -426,8 +410,6 @@ void spapr_drc_reset(sPAPRDRConnector *drc) spapr_drc_release(drc); } - drc->awaiting_allocation = false; - if (drc->dev) { /* A device present at reset is coldplugged */ drc->isolation_state = SPAPR_DR_ISOLATION_STATE_UNISOLATED; @@ -493,7 +475,6 @@ static const VMStateDescription vmstate_spapr_drc = { VMSTATE_UINT32(dr_indicator, sPAPRDRConnector), VMSTATE_BOOL(configured, sPAPRDRConnector), VMSTATE_BOOL(awaiting_release, sPAPRDRConnector), - VMSTATE_BOOL(awaiting_allocation, sPAPRDRConnector), VMSTATE_END_OF_LIST() } }; -- cgit v1.2.3-55-g7522