A few years back intel published a spec update:
http://www.intel.com/content/dam/doc/specification-update/5520-and-5500-chipset-ioh-specification-update.pdf
For the 5520 and 5500 chipsets which contained an errata (specificially errata
53), which noted that these chipsets can't properly do interrupt remapping, and
as a result the recommend that interrupt remapping be disabled in bios. While
many vendors have a bios update to do exactly that, not all do, and of course
not all users update their bios to a level that corrects the problem. As a
result, occasionally interrupts can arrive at a cpu even after affinity for that
interrupt has be moved, leading to lost or spurrious interrupts (usually
characterized by the message:
kernel: do_IRQ: 7.71 No irq handler for vector (irq -1)
There have been several incidents recently of people seeing this error, and
investigation has shown that they have system for which their BIOS level is such
that this feature was not properly turned off. As such, it would be good to
give them a reminder that their systems are vulnurable to this problem. For
details of those that reported the problem, please see:
https://bugzilla.redhat.com/show_bug.cgi?id=887006
[ Joerg: Removed CONFIG_IRQ_REMAP ifdef from early-quirks.c ]
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Prarit Bhargava <prarit@redhat.com>
CC: Don Zickus <dzickus@redhat.com>
CC: Don Dutile <ddutile@redhat.com>
CC: Bjorn Helgaas <bhelgaas@google.com>
CC: Asit Mallick <asit.k.mallick@intel.com>
CC: David Woodhouse <dwmw2@infradead.org>
CC: linux-pci@vger.kernel.org
CC: Joerg Roedel <joro@8bytes.org>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Arkadiusz Miśkiewicz <arekm@maven.pl>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
Current kernels print this on my Dell server:
------------[ cut here ]------------
WARNING: at drivers/iommu/intel_irq_remapping.c:542
intel_enable_irq_remapping+0x7b/0x27e()
Hardware name: PowerEdge R620
Your BIOS is broken and requested that x2apic be disabled
This will leave your machine vulnerable to irq-injection attacks
Use 'intremap=no_x2apic_optout' to override BIOS request
[...]
Enabled IRQ remapping in xapic mode
x2apic not enabled, IRQ remapping is in xapic mode
This is inconsistent with itself -- interrupt remapping is *on*.
Fix the mess by making the warnings say what they mean and my
making sure that compatibility format interrupts (the dangerous
ones) are disabled if x2apic is present regardless of BIOS
settings.
With this patch applied, the output is:
Your BIOS is broken and requested that x2apic be disabled.
This will slightly decrease performance.
Use 'intremap=no_x2apic_optout' to override BIOS request.
Enabled IRQ remapping in xapic mode
x2apic not enabled, IRQ remapping is in xapic mode
This should make us as or more secure than we are now and
replace a rather scary warning with a much less scary warning on
silly but functional systems.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Link: http://lkml.kernel.org/r/2011b943a886fd7c46079eb10bc24fc130587503.1359759303.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move all the code to either to the header file
asm/irq_remapping.h or to drivers/iommu/.
Signed-off-by: Joerg Roedel <joro@8bytes.org>
Acked-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This call-back is used to dump IO-APIC entries for debugging
purposes into the kernel log. VT-d needs a special routine
for this and will overwrite the default.
Signed-off-by: Joerg Roedel <joro@8bytes.org>
Acked-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The ACPI tables in the Macbook Air 5,1 define a single IOAPIC with id 2,
but the only remapping unit described in the DMAR table matches id 0.
Interrupt remapping fails as a result, and the kernel panics with the
message "timer doesn't work through Interrupt-remapped IO-APIC."
To fix this, check each IOAPIC for a corresponding IOMMU. If an IOMMU is
not found, do not allow IRQ remapping to be enabled.
v2: Move check to parse_ioapics_under_ir(), raise log level to KERN_ERR,
and add FW_BUG to the log message
v3: Skip check if IOMMU doesn't support interrupt remapping and remove
existing check that the IOMMU count equals the IOAPIC count
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Move the ->irq_set_affinity() routines out of the #ifdef CONFIG_SMP
sections and use config_enabled(CONFIG_SMP) checks inside those
routines. Thus making those routines simple null stubs for
!CONFIG_SMP and retaining those routines with no additional
runtime overhead for CONFIG_SMP kernels.
Cleans up the ifdef CONFIG_SMP in and around routines related to
irq_set_affinity in io_apic and irq_remapping subsystems.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: torvalds@linux-foundation.org
Cc: joerg.roedel@amd.com
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: http://lkml.kernel.org/r/1339723729.3475.63.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is an extra semicolon here so the pr_err() message is
printed when it is not intended.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: Alexander Gordeev <agordeev@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/20120612162633.GA11077@elgon.mountain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Current cpu_mask_to_apicid() and cpu_mask_to_apicid_and()
implementations have few shortcomings:
1. A value returned by cpu_mask_to_apicid() is written to
hardware registers unconditionally. Should BAD_APICID get ever
returned it will be written to a hardware too. But the value of
BAD_APICID is not universal across all hardware in all modes and
might cause unexpected results, i.e. interrupts might get routed
to CPUs that are not configured to receive it.
2. Because the value of BAD_APICID is not universal it is
counter- intuitive to return it for a hardware where it does not
make sense (i.e. x2apic).
3. cpu_mask_to_apicid_and() operation is thought as an
complement to cpu_mask_to_apicid() that only applies a AND mask
on top of a cpumask being passed. Yet, as consequence of 18374d8
commit the two operations are inconsistent in that of:
cpu_mask_to_apicid() should not get a offline CPU with the cpumask
cpu_mask_to_apicid_and() should not fail and return BAD_APICID
These limitations are impossible to realize just from looking at
the operations prototypes.
Most of these shortcomings are resolved by returning a error
code instead of BAD_APICID. As the result, faults are reported
back early rather than possibilities to cause a unexpected
behaviour exist (in case of [1]).
The only exception is setup_timer_IRQ0_pin() routine. Although
obviously controversial to this fix, its existing behaviour is
preserved to not break the fragile check_timer() and would
better addressed in a separate fix.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131559.GF4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Make the file names consistent with the naming conventions of irq subsystem.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Neil Horman