83 lines
3.3 KiB
Diff
83 lines
3.3 KiB
Diff
From 5dd7cdf3739c73d910d5df6443b39e9b0b79f3fd Mon Sep 17 00:00:00 2001
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From: Laurent Vivier <lvivier@redhat.com>
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Date: Tue, 8 Sep 2020 18:47:16 -0400
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Subject: [PATCH 4/4] ppc/spapr: Use start-powered-off CPUState property
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RH-Author: Laurent Vivier <lvivier@redhat.com>
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Message-id: <20200908184716.1125192-4-lvivier@redhat.com>
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Patchwork-id: 98302
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O-Subject: [RHEL-AV-8.3.0 qemu-kvm PATCH 3/3] ppc/spapr: Use start-powered-off CPUState property
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Bugzilla: 1849483
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Acked-by: David Gibson <dgibson@redhat.com>
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RH-Acked-by: Greg Kurz <gkurz@redhat.com>
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From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
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PowerPC sPAPR CPUs start in the halted state, and spapr_reset_vcpu()
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attempts to implement this by setting CPUState::halted to 1. But that's too
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late for the case of hotplugged CPUs in a machine configure with 2 or more
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threads per core.
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By then, other parts of QEMU have already caused the vCPU to run in an
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unitialized state a couple of times. For example, ppc_cpu_reset() calls
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ppc_tlb_invalidate_all(), which ends up calling async_run_on_cpu(). This
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kicks the new vCPU while it has CPUState::halted = 0, causing QEMU to issue
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a KVM_RUN ioctl on the new vCPU before the guest is able to make the
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start-cpu RTAS call to initialize its register state.
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This problem doesn't seem to cause visible issues for regular guests, but
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on a secure guest running under the Ultravisor it does. The Ultravisor
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relies on being able to snoop on the start-cpu RTAS call to map vCPUs to
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guests, and this issue causes it to see a stray vCPU that doesn't belong to
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any guest.
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Fix by setting the start-powered-off CPUState property in
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spapr_create_vcpu(), which makes cpu_common_reset() initialize
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CPUState::halted to 1 at an earlier moment.
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Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
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Acked-by: David Gibson <david@gibson.dropbear.id.au>
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Reviewed-by: Greg Kurz <groug@kaod.org>
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Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
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Message-Id: <20200826055535.951207-4-bauerman@linux.ibm.com>
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Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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(cherry picked from commit 554c2169e9251ca2829ab968bd9ba5641a5abe1d)
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Signed-off-by: Laurent Vivier <lvivier@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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hw/ppc/spapr_cpu_core.c | 10 +++++-----
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1 file changed, 5 insertions(+), 5 deletions(-)
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diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
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index f228f8bb75..86fed5c528 100644
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--- a/hw/ppc/spapr_cpu_core.c
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+++ b/hw/ppc/spapr_cpu_core.c
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@@ -37,11 +37,6 @@ static void spapr_reset_vcpu(PowerPCCPU *cpu)
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cpu_reset(cs);
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- /* All CPUs start halted. CPU0 is unhalted from the machine level
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- * reset code and the rest are explicitly started up by the guest
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- * using an RTAS call */
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- cs->halted = 1;
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-
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env->spr[SPR_HIOR] = 0;
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lpcr = env->spr[SPR_LPCR];
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@@ -287,6 +282,11 @@ static PowerPCCPU *spapr_create_vcpu(SpaprCpuCore *sc, int i, Error **errp)
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cs = CPU(obj);
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cpu = POWERPC_CPU(obj);
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+ /*
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+ * All CPUs start halted. CPU0 is unhalted from the machine level reset code
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+ * and the rest are explicitly started up by the guest using an RTAS call.
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+ */
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+ cs->start_powered_off = true;
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cs->cpu_index = cc->core_id + i;
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spapr_set_vcpu_id(cpu, cs->cpu_index, &local_err);
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if (local_err) {
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--
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2.27.0
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