From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50433) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDnN4-0005bd-EY for qemu-devel@nongnu.org; Fri, 17 Jun 2016 02:35:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDnMy-0008FC-JV for qemu-devel@nongnu.org; Fri, 17 Jun 2016 02:35:13 -0400 From: David Gibson Date: Fri, 17 Jun 2016 16:36:30 +1000 Message-Id: <1466145399-32209-10-git-send-email-david@gibson.dropbear.id.au> In-Reply-To: <1466145399-32209-1-git-send-email-david@gibson.dropbear.id.au> References: <1466145399-32209-1-git-send-email-david@gibson.dropbear.id.au> Subject: [Qemu-devel] [PULL 09/18] spapr_drc: Prevent detach racing against attach for CPU DR List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: peter.maydell@linaro.org Cc: agraf@suse.de, aik@ozlabs.ru, bharata@linux.vnet.ibm.com, imammedo@redhat.com, mdroth@linux.vnet.ibm.com, qemu-ppc@nongnu.org, qemu-devel@nongnu.org, David Gibson 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 --- 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 94c875d..d276db3a 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; @@ -373,6 +375,10 @@ 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), @@ -421,6 +427,12 @@ 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; -- 2.5.5