vfio-pci: Make host MSI-X enable track guest

Guests typically enable MSI-X with all of the vectors in the MSI-X
vector table masked.  Only when the vector is enabled does the vector
get unmasked, resulting in a vector_use callback.  These two points,
enable and unmask, correspond to pci_enable_msix() and request_irq()
for Linux guests.  Some drivers rely on VF/PF or PF/fw communication
channels that expect the physical state of the device to match the
guest visible state of the device.  They don't appreciate lazily
enabling MSI-X on the physical device.

To solve this, enable MSI-X with a single vector when the MSI-X
capability is enabled and immediate disable the vector.  This leaves
the physical device in exactly the same state between host and guest.
Furthermore, the brief gap where we enable vector 0, it fires into
userspace, not KVM, so the guest doesn't get spurious interrupts.
Ideally we could call VFIO_DEVICE_SET_IRQS with the right parameters
to enable MSI-X with zero vectors, but this will currently return an
error as the Linux MSI-X interfaces do not allow it.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Cc: qemu-stable@nongnu.org
vfio-pci: Loosen sanity checks to allow future features

VFIO_PCI_NUM_REGIONS and VFIO_PCI_NUM_IRQS should never have been
used in this manner as it locks a specific kernel implementation.
Future features may introduce new regions or interrupt entries
(VGA may add legacy ranges, AER might add an IRQ for error
signalling).  Fix this before it gets us into trouble.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Cc: qemu-stable@nongnu.org
Check return values from g_poll and select

The current implementation of os_host_main_loop_wait() on Windows,
returns 1 only when a g_poll() event occurs because the return value of
select() is overridden. This is wrong as we may skip a socket event, as
shown in this example:

1. select() returns 0
2. g_poll() returns 1  (socket event occurs)
3. os_host_main_loop_wait() returns 1
4. qemu_iohandler_poll() sees no socket event because select() has
   return before the event occurs
5. select() returns 1
6. g_poll() returns 0 (g_poll overrides select's return value)
7. os_host_main_loop_wait() returns 0
8. qemu_iohandler_poll() doesn't check for socket events because the
   return value of os_host_main_loop_wait() is zero.
9. goto 5

This patch use one variable for each of these return values, so we don't
miss a select() event anymore.

Also move the call to select() after g_poll(), this will improve latency
as we don't have to go through two os_host_main_loop_wait() calls to
detect a socket event.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
rtc-test: skip year-2038 overflow check in case time_t is 32bit only

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
m48t59-test: don't touch watchdog

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Merge remote-tracking branch 'awilliam/tags/qemu-1.4-vfio-20130109.0' into staging

vfio-pci: Fixes for qemu 1.4 & stable

* awilliam/tags/qemu-1.4-vfio-20130109.0:
  vfio-pci: Loosen sanity checks to allow future features
  vfio-pci: Make host MSI-X enable track guest

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Merge remote-tracking branch 'kraxel/build.1' into staging

* kraxel/build.1:
  m48t59-test: don't touch watchdog
  rtc-test: skip year-2038 overflow check in case time_t is 32bit only

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
cpu: Move nr_{cores,threads} fields to CPUState

To facilitate the field movements, pass MIPSCPU to malta_mips_config();
avoid that for mips_cpu_map_tc() since callers only access MIPS Thread
Contexts, inside TCG helpers.

Signed-off-by: Andreas Färber <afaerber@suse.de>
target-mips: Clean up mips_cpu_map_tc() documentation

This function will be touched again soon, so a good understanding of env
vs. other helps. Adopt gtk-doc style.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Eric Johnson <ericj@mips.com>
cpu: Move numa_node field to CPUState

Signed-off-by: Andreas Färber <afaerber@suse.de>
cpu: Move cpu_index field to CPUState

Note that target-alpha accesses this field from TCG, now using a
negative offset. Therefore the field is placed last in CPUState.

Pass PowerPCCPU to [kvm]ppc_fixup_cpu() to facilitate this change.

Move common parts of mips cpu_state_reset() to mips_cpu_reset().

Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Richard Henderson <rth@twiddle.net> (for alpha)
kvm: Pass CPUState to kvm_init_vcpu()

CPUArchState is no longer needed, and it thereby no longer depends on
NEED_CPU_H.

Signed-off-by: Andreas Färber <afaerber@suse.de>
xen: Simplify halting of first CPU

Use the global first_cpu variable to halt the CPU rather than using a
local first_cpu initialized from qemu_get_cpu(0).

This will allow to change qemu_get_cpu() return type to CPUState
despite use of the CPU_COMMON halted field in the reset handler.

Signed-off-by: Andreas Färber <afaerber@suse.de>
exec: Return CPUState from qemu_get_cpu()

Move the declaration to qemu/cpu.h and add documentation.
The implementation still depends on CPUArchState for CPU iteration.

Signed-off-by: Andreas Färber <afaerber@suse.de>
kvm: Add fake KVM constants to avoid #ifdefs on KVM-specific code

Any KVM-specific code that use these constants must check if
kvm_enabled() is true before using them.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: Disable kvm_mmu by default

KVM_CAP_PV_MMU capability reporting was removed from the kernel since
v2.6.33 (see commit a68a6a7282373), and was completely removed from the
kernel since v3.3 (see commit fb92045843). It doesn't make sense to keep
it enabled by default, as it would cause unnecessary hassle when using
the "enforce" flag.

This disables kvm_mmu on all machine-types. With this fix, the possible
scenarios when migrating from QEMU <= 1.3 to QEMU 1.4 are:

------------+----------+----------------------------------------------------
 src kernel | dst kern.| Result
------------+----------+----------------------------------------------------
 >= 2.6.33  | any      | kvm_mmu was already disabled and will stay disabled
 <= 2.6.32  | >= 3.3   | correct live migration is impossible
 <= 2.6.32  | <= 3.2   | kvm_mmu will be disabled on next guest reboot *
------------+----------+----------------------------------------------------

 * If they are running kernel <= 2.6.32 and want kvm_mmu to be kept
   enabled on guest reboot, they can explicitly add +kvm_mmu to the QEMU
   command-line. Using 2.6.33 and higher, it is not possible to enable
   kvm_mmu explicitly anymore.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386/cpu: Introduce FeatureWord typedefs

This introduces a FeatureWord enum, FeatureWordInfo struct (with
generation information about a feature word), and a FeatureWordArray
typedef, and changes add_flagname_to_bitmaps() code and
cpu_x86_parse_featurestr() to use the new typedefs instead of separate
variables for each feature word.

This will help us keep the code at kvm_check_features_against_host(),
cpu_x86_parse_featurestr() and add_flagname_to_bitmaps() sane while
adding new feature name arrays.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: kvm_check_features_against_host(): Use feature_word_info

Instead of carrying the CPUID leaf/register and feature name array on
the model_features_t struct, move that information into
feature_word_info so it can be reused by other functions.

The goal is to eventually kill model_features_t entirely, but to do that
we have to either convert x86_def_t.features to an array or use
offsetof() inside FeatureWordInfo (to replace the pointers inside
model_features_t). So by now just move most of the model_features_t
fields to FeatureWordInfo except for the two pointers to local
arguments.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386/cpu.c: Add feature name array for ext4_features

Feature names were taken from the X86_FEATURE_* constants in the Linux
kernel code.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
target-i386: check/enforce: Check all feature words

This adds the following feature words to the list of flags to be checked
by kvm_check_features_against_host():

 - cpuid_7_0_ebx_features
 - ext4_features
 - kvm_features
 - svm_features

This will ensure the "enforce" flag works as it should: it won't allow
QEMU to be started unless every flag that was requested by the user or
defined in the CPU model is supported by the host.

This patch may cause existing configurations where "enforce" wasn't
preventing QEMU from being started to abort QEMU. But that's exactly the
point of this patch: if a flag was not supported by the host and QEMU
wasn't aborting, it was a bug in the "enforce" code.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>