Cluster x2APIC cannot work without KVM's x2apic API when the maximal
APIC ID is greater than 8 and only KVM's LAPIC can support x2APIC, so we
forbid other APICs and also the old KVM case with less than 9, to
simplify the code.
There is no point in enabling EIM in forbidden APICs, so we keep it
enabled only for the KVM APIC; unconditionally, because making the
option depend on KVM version would be a maintanance burden.
Old QEMUs would enable eim whenever intremap was on, which would trick
guests into thinking that they can enable cluster x2APIC even if any
interrupt destination would get clamped to 8 bits.
Depending on your configuration, QEMU could notice that the destination
LAPIC is not present and report it with a very non-obvious:
KVM: injection failed, MSI lost (Operation not permitted)
Or the guest could say something about unexpected interrupts, because
clamping leads to aliasing so interrupts were being delivered to
incorrect VCPUs.
KVM_X2APIC_API is the feature that allows us to enable EIM for KVM.
QEMU 2.7 allowed EIM whenever interrupt remapping was enabled. In order
to keep backward compatibility, we again allow guests to misbehave in
non-obvious ways, and make it the default for old machine types.
A user can enable the buggy mode it with "x-buggy-eim=on".
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
The parsing of KVM_SET_LAPIC's input depends on the current value of the
APIC base MSR---which indeed is stored in APICCommonState---but for historical
reasons APIC base is set through KVM_SET_SREGS together with cr8 (which is
really just the APIC TPR) and the actual "special CPU registers".
APIC base must now be set before the actual LAPIC registers, so do that
in kvm_apic_put. It will be set again to the same value with KVM_SET_SREGS,
but that's not a big issue.
This only happens since Linux 4.8, which checks for x2apic mode in
KVM_SET_LAPIC. However it's really a QEMU bug; until the recent
commit 78d6a05 ("x86/lapic: Load LAPIC state at post_load", 2016-09-13)
QEMU was indeed setting APIC base (via KVM_SET_SREGS) before the other
LAPIC registers.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch adds support for split IRQ chip mode. When
KVM_CAP_SPLIT_IRQCHIP is enabled:
1.) The PIC, PIT, and IOAPIC are implemented in userspace while
the LAPIC is implemented by KVM.
2.) The software IOAPIC delivers interrupts to the KVM LAPIC via
kvm_set_irq. Interrupt delivery is configured via the MSI routing
table, for which routes are reserved in target-i386/kvm.c then
configured in hw/intc/ioapic.c
3.) KVM delivers IOAPIC EOIs via a new exit KVM_EXIT_IOAPIC_EOI,
which is handled in target-i386/kvm.c and relayed to the software
IOAPIC via ioapic_eoi_broadcast.
Signed-off-by: Matt Gingell <gingell@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The commit 317b0a6d8 fixed an issue which caused by the outdated
env->tsc value, but the fix lead to 'cpu_synchronize_all_states()'
called twice during live migration. The 'cpu_synchronize_all_states()'
takes about 130us for a VM which has 4 vcpus, it's a bit expensive.
Synchronize the whole CPU context just for updating env->tsc is too
wasting, this patch use a new function to update the env->tsc.
Comparing to 'cpu_synchronize_all_states()', it only takes about 20us.
Signed-off-by: Liang Li <liang.z.li@intel.com>
Message-Id: <1446695464-27116-2-git-send-email-liang.z.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The property can take values on, off or auto. The default is "off"
for KVM and pre-2.4 machines, otherwise "auto" (which makes it
available on TCG or on new-enough kernels).
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that we have a CPU object with a reset method, it is better to
keep the KVM reset close to the CPU reset. Using qemu_register_reset
as we do now keeps them far apart.
With this patch, PPC no longer calls the kvm_arch_ function, so
it can get removed there. Other arches call it from their CPU
reset handler, and the function gets an ARMCPU/X86CPU/S390CPU.
Note that ARM- and s390-specific functions are called kvm_arm_*
and kvm_s390_*, while x86-specific functions are called kvm_arch_*.
That follows the convention used by the different architectures.
Changing that is the topic of a separate patch.
Reviewed-by: Gleb Natapov <gnatapov@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
These helpers abstract the interaction of upcoming pci-assign with the
KVM kernel services. Put them under i386 only as other archs will
implement device pass-through via VFIO and not this classic interface.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
kvm_allows_irq0_override() is a totally x86 specific concept:
move it to the target-specific source file where it belongs.
This means we need a new header file for the prototype:
kvm_i386.h, in line with the existing kvm_ppc.h.
While we are moving it, fix the return type to be 'bool' rather
than 'int'.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
