From 92a89364e07b07d1fcf5c338bca3d2ff9f535a72 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 12 Jul 2016 07:41:41 +0200 Subject: [PATCH 08/34] spapr_drc: Prevent detach racing against attach for CPU DR RH-Author: David Gibson Message-id: <1468309320-14859-9-git-send-email-dgibson@redhat.com> Patchwork-id: 71128 O-Subject: [RHEL7.3 qemu-kvm-rhev PATCHv2 08/27] spapr_drc: Prevent detach racing against attach for CPU DR Bugzilla: 1172917 RH-Acked-by: Igor Mammedov RH-Acked-by: Laurent Vivier RH-Acked-by: Thomas Huth From: Bharata B Rao If a CPU is hot removed while hotplug of the same is still in progress, the guest crashes. Prevent this by ensuring that detach is done only after attach has completed. The existing code already prevents such race for PCI hotplug. However given that CPU is a logical DR unlike PCI and starts with ISOLATED state, we need a logic that works for CPU too. Signed-off-by: Bharata B Rao Reviewed-by: Michael Roth Signed-off-by: Michael Roth [Don't set awaiting_attach for PCI devices] Signed-off-by: David Gibson (cherry picked from commit aab99135b63522267c6fdae04712cb2f02c8c7de) Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1172917 Signed-off-by: David Gibson Signed-off-by: Miroslav Rezanina --- hw/ppc/spapr_drc.c | 12 ++++++++++++ include/hw/ppc/spapr_drc.h | 1 + 2 files changed, 13 insertions(+) diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c index 1f5f1d7..e146267 100644 --- a/hw/ppc/spapr_drc.c +++ b/hw/ppc/spapr_drc.c @@ -140,6 +140,8 @@ static uint32_t set_allocation_state(sPAPRDRConnector *drc, DPRINTFN("finalizing device removal"); drck->detach(drc, DEVICE(drc->dev), drc->detach_cb, drc->detach_cb_opaque, NULL); + } else if (drc->allocation_state == SPAPR_DR_ALLOCATION_STATE_USABLE) { + drc->awaiting_allocation = false; } } return RTAS_OUT_SUCCESS; @@ -376,6 +378,10 @@ static void attach(sPAPRDRConnector *drc, DeviceState *d, void *fdt, drc->signalled = (drc->type != SPAPR_DR_CONNECTOR_TYPE_PCI) ? true : coldplug; + if (drc->type != 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), @@ -424,6 +430,12 @@ static void detach(sPAPRDRConnector *drc, DeviceState *d, return; } + if (drc->awaiting_allocation) { + drc->awaiting_release = true; + DPRINTFN("awaiting allocation to complete before removal"); + return; + } + drc->indicator_state = SPAPR_DR_INDICATOR_STATE_INACTIVE; if (drc->detach_cb) { diff --git a/include/hw/ppc/spapr_drc.h b/include/hw/ppc/spapr_drc.h index fa21ba0..08e8411 100644 --- a/include/hw/ppc/spapr_drc.h +++ b/include/hw/ppc/spapr_drc.h @@ -152,6 +152,7 @@ typedef struct sPAPRDRConnector { bool awaiting_release; bool signalled; + bool awaiting_allocation; /* device pointer, via link property */ DeviceState *dev; -- 1.8.3.1