linux.git/arch/powerpc/sysdev/xive/common.c, branch v5.15 Linux kernel source tree powerpc/xive: Discard disabled interrupts in get_irqchip_state() 2021-10-13T05:38:55+00:00 Cédric Le Goater clg@kaod.org 2021-10-11T07:02:03+00:00 6f779e1d359b8d5801f677c1d49dcfa10bf95674 When an interrupt is passed through, the KVM XIVE device calls the set_vcpu_affinity() handler which raises the P bit to mask the interrupt and to catch any in-flight interrupts while routing the interrupt to the guest. On the guest side, drivers (like some Intels) can request at probe time some MSIs and call synchronize_irq() to check that there are no in flight interrupts. This will call the XIVE get_irqchip_state() handler which will always return true as the interrupt P bit has been set on the host side and lock the CPU in an infinite loop. Fix that by discarding disabled interrupts in get_irqchip_state(). Fixes: da15c03b047d ("powerpc/xive: Implement get_irqchip_state method for XIVE to fix shutdown race") Cc: stable@vger.kernel.org #v5.4+ Signed-off-by: Cédric Le Goater <clg@kaod.org> Tested-by: seeteena <s1seetee@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211011070203.99726-1-clg@kaod.org 
When an interrupt is passed through, the KVM XIVE device calls the
set_vcpu_affinity() handler which raises the P bit to mask the
interrupt and to catch any in-flight interrupts while routing the
interrupt to the guest.

On the guest side, drivers (like some Intels) can request at probe
time some MSIs and call synchronize_irq() to check that there are no
in flight interrupts. This will call the XIVE get_irqchip_state()
handler which will always return true as the interrupt P bit has been
set on the host side and lock the CPU in an infinite loop.

Fix that by discarding disabled interrupts in get_irqchip_state().

Fixes: da15c03b047d ("powerpc/xive: Implement get_irqchip_state method for XIVE to fix shutdown race")
Cc: stable@vger.kernel.org #v5.4+
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Tested-by: seeteena <s1seetee@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211011070203.99726-1-clg@kaod.org
Merge branch 'fixes' into next 2021-09-03T12:54:12+00:00 Michael Ellerman mpe@ellerman.id.au 2021-09-03T12:54:12+00:00 a3314262eede9c909a0c797f16f25f941d12c78d Merge our fixes branch into next. That lets us resolve a conflict in arch/powerpc/sysdev/xive/common.c. Between cbc06f051c52 ("powerpc/xive: Do not skip CPU-less nodes when creating the IPIs"), which moved request_irq() out of xive_init_ipis(), and 17df41fec5b8 ("powerpc: use IRQF_NO_DEBUG for IPIs") which added IRQF_NO_DEBUG to that request_irq() call, which has now moved. 
Merge our fixes branch into next.

That lets us resolve a conflict in arch/powerpc/sysdev/xive/common.c.

Between cbc06f051c52 ("powerpc/xive: Do not skip CPU-less nodes when
creating the IPIs"), which moved request_irq() out of xive_init_ipis(),
and 17df41fec5b8 ("powerpc: use IRQF_NO_DEBUG for IPIs") which added
IRQF_NO_DEBUG to that request_irq() call, which has now moved.
powerpc/xive: Do not mark xive_request_ipi() as __init 2021-08-18T13:52:13+00:00 Nathan Chancellor nathan@kernel.org 2021-08-16T18:57:11+00:00 3f78c90f9eb2e228f44ecc8f4377753f0e11dbab Compiling ppc64le_defconfig with clang-14 shows a modpost warning: WARNING: modpost: vmlinux.o(.text+0xa74e0): Section mismatch in reference from the function xive_setup_cpu_ipi() to the function .init.text:xive_request_ipi() The function xive_setup_cpu_ipi() references the function __init xive_request_ipi(). This is often because xive_setup_cpu_ipi lacks a __init annotation or the annotation of xive_request_ipi is wrong. xive_request_ipi() is called from xive_setup_cpu_ipi(), which is not __init, so xive_request_ipi() should not be marked __init. Remove the attribute so there is no more warning. Fixes: cbc06f051c52 ("powerpc/xive: Do not skip CPU-less nodes when creating the IPIs") Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210816185711.21563-1-nathan@kernel.org 
Compiling ppc64le_defconfig with clang-14 shows a modpost warning:

WARNING: modpost: vmlinux.o(.text+0xa74e0): Section mismatch in
reference from the function xive_setup_cpu_ipi() to the function
.init.text:xive_request_ipi()
The function xive_setup_cpu_ipi() references
the function __init xive_request_ipi().
This is often because xive_setup_cpu_ipi lacks a __init
annotation or the annotation of xive_request_ipi is wrong.

xive_request_ipi() is called from xive_setup_cpu_ipi(), which is not
__init, so xive_request_ipi() should not be marked __init. Remove the
attribute so there is no more warning.

Fixes: cbc06f051c52 ("powerpc/xive: Do not skip CPU-less nodes when creating the IPIs")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210816185711.21563-1-nathan@kernel.org
powerpc: rename powerpc_debugfs_root to arch_debugfs_dir 2021-08-13T12:04:26+00:00 Aneesh Kumar K.V aneesh.kumar@linux.ibm.com 2021-08-12T13:28:31+00:00 dbf77fed8b302e87561c7c2fc06050c88f4d3120 No functional change in this patch. arch_debugfs_dir is the generic kernel name declared in linux/debugfs.h for arch-specific debugfs directory. Architectures like x86/s390 already use the name. Rename powerpc specific powerpc_debugfs_root to arch_debugfs_dir. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210812132831.233794-2-aneesh.kumar@linux.ibm.com 
No functional change in this patch. arch_debugfs_dir is the generic kernel
name declared in linux/debugfs.h for arch-specific debugfs directory.
Architectures like x86/s390 already use the name. Rename powerpc
specific powerpc_debugfs_root to arch_debugfs_dir.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210812132831.233794-2-aneesh.kumar@linux.ibm.com
powerpc/xive: Do not skip CPU-less nodes when creating the IPIs 2021-08-12T12:31:41+00:00 Cédric Le Goater clg@kaod.org 2021-08-07T07:20:57+00:00 cbc06f051c524dcfe52ef0d1f30647828e226d30 On PowerVM, CPU-less nodes can be populated with hot-plugged CPUs at runtime. Today, the IPI is not created for such nodes, and hot-plugged CPUs use a bogus IPI, which leads to soft lockups. We can not directly allocate and request the IPI on demand because bringup_up() is called under the IRQ sparse lock. The alternative is to allocate the IPIs for all possible nodes at startup and to request the mapping on demand when the first CPU of a node is brought up. Fixes: 7dcc37b3eff9 ("powerpc/xive: Map one IPI interrupt per node") Cc: stable@vger.kernel.org # v5.13 Reported-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com> Signed-off-by: Cédric Le Goater <clg@kaod.org> Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Tested-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210807072057.184698-1-clg@kaod.org 
On PowerVM, CPU-less nodes can be populated with hot-plugged CPUs at
runtime. Today, the IPI is not created for such nodes, and hot-plugged
CPUs use a bogus IPI, which leads to soft lockups.

We can not directly allocate and request the IPI on demand because
bringup_up() is called under the IRQ sparse lock. The alternative is
to allocate the IPIs for all possible nodes at startup and to request
the mapping on demand when the first CPU of a node is brought up.

Fixes: 7dcc37b3eff9 ("powerpc/xive: Map one IPI interrupt per node")
Cc: stable@vger.kernel.org # v5.13
Reported-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210807072057.184698-1-clg@kaod.org
powerpc: use IRQF_NO_DEBUG for IPIs 2021-08-10T13:15:01+00:00 Cédric Le Goater clg@kaod.org 2021-07-19T13:06:14+00:00 17df41fec5b80b16ea4774495f1eb730e2225619 There is no need to use the lockup detector ("noirqdebug") for IPIs. The ipistorm benchmark measures a ~10% improvement on high systems when this flag is set. Signed-off-by: Cédric Le Goater <clg@kaod.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210719130614.195886-1-clg@kaod.org 
There is no need to use the lockup detector ("noirqdebug") for IPIs.
The ipistorm benchmark measures a ~10% improvement on high systems
when this flag is set.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210719130614.195886-1-clg@kaod.org
powerpc/xive: Use XIVE domain under xmon and debugfs 2021-08-10T13:15:01+00:00 Cédric Le Goater clg@kaod.org 2021-07-01T13:27:49+00:00 59b2bc18b1492b46d45b6b6828ba098f09b9ba67 The default domain of the PCI/MSIs is not the XIVE domain anymore. To list the IRQ mappings under XMON and debugfs, query the IRQ data from the low level XIVE domain. Signed-off-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210701132750.1475580-32-clg@kaod.org 
The default domain of the PCI/MSIs is not the XIVE domain anymore. To
list the IRQ mappings under XMON and debugfs, query the IRQ data from
the low level XIVE domain.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210701132750.1475580-32-clg@kaod.org
powerpc/pseries/pci: Add a msi_free() handler to clear XIVE data 2021-08-10T13:14:58+00:00 Cédric Le Goater clg@kaod.org 2021-07-01T13:27:27+00:00 9a014f456881e947bf8cdd8c984a207097e6c096 The MSI domain clears the IRQ with msi_domain_free(), which calls irq_domain_free_irqs_top(), which clears the handler data. This is a problem for the XIVE controller since we need to unmap MMIO pages and free a specific XIVE structure. The 'msi_free()' handler is called before irq_domain_free_irqs_top() when the handler data is still available. Use that to clear the XIVE controller data. Signed-off-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210701132750.1475580-10-clg@kaod.org 
The MSI domain clears the IRQ with msi_domain_free(), which calls
irq_domain_free_irqs_top(), which clears the handler data. This is a
problem for the XIVE controller since we need to unmap MMIO pages and
free a specific XIVE structure.

The 'msi_free()' handler is called before irq_domain_free_irqs_top()
when the handler data is still available. Use that to clear the XIVE
controller data.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210701132750.1475580-10-clg@kaod.org
powerpc/xive: Remove irqd_is_started() check when setting the affinity 2021-08-10T13:14:57+00:00 Cédric Le Goater clg@kaod.org 2021-07-01T13:27:25+00:00 292145a6e598c1e6633b8f5f607706b46f552ab9 In the early days of XIVE support, commit cffb717ceb8e ("powerpc/xive: Ensure active irqd when setting affinity") tried to fix an issue related to interrupt migration. If the root cause was related to CPU unplug, it should have been fixed and there is no reason to keep the irqd_is_started() check. This test is also breaking affinity setting of MSIs which can set before starting the associated IRQ. Signed-off-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210701132750.1475580-8-clg@kaod.org 
In the early days of XIVE support, commit cffb717ceb8e ("powerpc/xive:
Ensure active irqd when setting affinity") tried to fix an issue
related to interrupt migration. If the root cause was related to CPU
unplug, it should have been fixed and there is no reason to keep the
irqd_is_started() check. This test is also breaking affinity setting
of MSIs which can set before starting the associated IRQ.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210701132750.1475580-8-clg@kaod.org
powerpc/xive: Drop unmask of MSIs at startup 2021-08-10T13:14:57+00:00 Cédric Le Goater clg@kaod.org 2021-07-01T13:27:24+00:00 5690bcae186084a8544b1819f0d89399268bd0cf That was a workaround in the XIVE domain because of the lack of MSI domain. This is now handled. Signed-off-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210701132750.1475580-7-clg@kaod.org 
That was a workaround in the XIVE domain because of the lack of MSI
domain. This is now handled.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210701132750.1475580-7-clg@kaod.org