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| author | Thiago Jung Bauermann <bauerman@linux.ibm.com> | 2020-08-26 02:55:30 -0300 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2020-09-08 10:08:43 +1000 |
| commit | 554c2169e9251ca2829ab968bd9ba5641a5abe1d (patch) | |
| tree | 6372516d8119f09e8e5c8c7cfe5e34d8e58f7278 /hw | |
| parent | 6ad1da667c8e21f019d4adc21702e06dd9225790 (diff) | |
| download | qemu-554c2169e9251ca2829ab968bd9ba5641a5abe1d.zip qemu-554c2169e9251ca2829ab968bd9ba5641a5abe1d.tar.gz qemu-554c2169e9251ca2829ab968bd9ba5641a5abe1d.tar.bz2 | |
ppc/spapr: Use start-powered-off CPUState property
PowerPC sPAPR CPUs start in the halted state, and spapr_reset_vcpu()
attempts to implement this by setting CPUState::halted to 1. But that's too
late for the case of hotplugged CPUs in a machine configure with 2 or more
threads per core.
By then, other parts of QEMU have already caused the vCPU to run in an
unitialized state a couple of times. For example, ppc_cpu_reset() calls
ppc_tlb_invalidate_all(), which ends up calling async_run_on_cpu(). This
kicks the new vCPU while it has CPUState::halted = 0, causing QEMU to issue
a KVM_RUN ioctl on the new vCPU before the guest is able to make the
start-cpu RTAS call to initialize its register state.
This problem doesn't seem to cause visible issues for regular guests, but
on a secure guest running under the Ultravisor it does. The Ultravisor
relies on being able to snoop on the start-cpu RTAS call to map vCPUs to
guests, and this issue causes it to see a stray vCPU that doesn't belong to
any guest.
Fix by setting the start-powered-off CPUState property in
spapr_create_vcpu(), which makes cpu_common_reset() initialize
CPUState::halted to 1 at an earlier moment.
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Message-Id: <20200826055535.951207-4-bauerman@linux.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/ppc/spapr_cpu_core.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c index c4f47dc..2125fda 100644 --- a/hw/ppc/spapr_cpu_core.c +++ b/hw/ppc/spapr_cpu_core.c @@ -36,11 +36,6 @@ static void spapr_reset_vcpu(PowerPCCPU *cpu) cpu_reset(cs); - /* All CPUs start halted. CPU0 is unhalted from the machine level - * reset code and the rest are explicitly started up by the guest - * using an RTAS call */ - cs->halted = 1; - env->spr[SPR_HIOR] = 0; lpcr = env->spr[SPR_LPCR]; @@ -274,6 +269,11 @@ static PowerPCCPU *spapr_create_vcpu(SpaprCpuCore *sc, int i, Error **errp) cs = CPU(obj); cpu = POWERPC_CPU(obj); + /* + * All CPUs start halted. CPU0 is unhalted from the machine level reset code + * and the rest are explicitly started up by the guest using an RTAS call. + */ + cs->start_powered_off = true; cs->cpu_index = cc->core_id + i; spapr_set_vcpu_id(cpu, cs->cpu_index, &local_err); if (local_err) { |