KVM: Fix GSI number space limit

KVM tells us the number of GSIs it can handle inside the kernel. That value is
basically KVM_MAX_IRQ_ROUTES. However when we try to set the GSI mapping table,
it checks for

    r = -EINVAL;
    if (routing.nr >= KVM_MAX_IRQ_ROUTES)
        goto out;

erroring out even when we're only using all of the GSIs. To make sure we never
hit that limit, let's reduce the number of GSIs we get from KVM by one.

Cc: qemu-stable@nongnu.org
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
target-mips: Reset CPU timer consistently

The MIPS CPU timer (CP0 Count/Compare registers & QEMU timer) is
reset at machine initialisation, including starting the timeout. Both
registers however are placed before mvp in CPUMIPSState so they will
both be zeroed on reset by the memset in mips_cpu_reset() including soon
after init. This doesn't take into account that the timer may be
running, in which case env->CP0_Count will represent the delta against
the VM clock and the timeout will need updating.

At init time (cpu_mips_clock_init()), lets only create the timer.
Setting Count = 1 and starting the timer (cpu_mips_store_count()) can be
done at reset time from cpu_state_reset(), which is after the memset.
There is also no need to set CP0_Compare = 0 as that is already handled
by the memset.

Note that a reset occurs from mips_cpu_realizefn() which is before the
machine init callback has had a chance to set up the CPU interrupts and
the CPU timer, so env->timer will be NULL. This case is handled
explicitly in cpu_mips_store_count(), treating the timer as disabled
(which will also be the right thing to do when KVM support is added).

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hw/mips/cputimer: Don't start periodic timer in KVM mode

Compare/Count timer interrupts are handled in-kernel for KVM. Therefore
don't bother creating the timer at init time if KVM is enabled. This
will conveniently avoid attempts to set the timeout when
cpu_mips_store_count() is called at reset with KVM enabled, treating the
timer as stopped so that CP0_Count is modified directly.

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
[james.hogan@imgtec.com: Update after "target-mips: Reset CPU timer
consistently" which moves timer start to reset time]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hw/mips: Add API to convert KVM guest KSEG0 <-> GPA

Add API for converting physical addresses to KVM guest KSEG0 addresses,
and fix the existing API for converting KSEG0 addresses to physical
addresses to work in the KVM case. Both have the same sized KSEG0, so
it's just a case of fixing the mask.

In KVM trap and emulate mode both the guest kernel and guest userspace
execute in useg:
    Guest User address space:   0x00000000..0x3fffffff
    Guest Kernel Unmapped:      0x40000000..0x5fffffff
    Guest Kernel Mapped:        0x60000000..0x7fffffff

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
target-mips: get_physical_address: Add defines for segment bases

Add preprocessor definitions for 32bit segment bases for use in
get_physical_address(). These will also be taken advantage of in the
next patch which adds KVM awareness.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
target-mips: get_physical_address: Add KVM awareness

MIPS KVM trap & emulate mode (which is currently the only supported
mode) has to add an extra kseg0/kseg1 at 0x40000000 and an extra
kseg2/kseg3 at 0x60000000. Take this into account in
get_physical_address() so that debug memory access works.

This is done by translating the address to a standard kseg0 or kseg2
address before doing the normal address translation. The real virtual
address is still used for TLB lookups.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm: Allow arch to set sigmask length

MIPS/Linux is unusual in having 128 signals rather than just 64 like
most other architectures. This means its sigmask is 16 bytes instead of
8, so allow arches to override the sigmask->len value passed to the
KVM_SET_SIGNAL_MASK ioctl in kvm_set_signal_mask() by calling
kvm_set_sigmask_len() from kvm_arch_init(). Otherwise default to 8
bytes.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Sanjay Lal <sanjayl@kymasys.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
target-mips: kvm: Add main KVM support for MIPS

Implement the main KVM arch API for MIPS.

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andreas Färber <afaerber@suse.de>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
target-mips: Call kvm_mips_reset_vcpu() from mips_cpu_reset()

When KVM is enabled call kvm_mips_reset_vcpu() from mips_cpu_reset() as
done for other targets since commit 50a2c6e55fa2 (kvm: reset state from
the CPU's reset method).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hw/mips: In KVM mode, inject IRQ2 (I/O) interrupts via ioctls

COP0 emulation is in-kernel for KVM, so inject IRQ2 (I/O) interrupts via
ioctls.

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hw/mips: malta: Add KVM support

In KVM mode the bootrom is loaded and executed from the last 1MB of
DRAM.

Based on "[PATCH 12/12] KVM/MIPS: General KVM support and support for
SMP Guests" by Sanjay Lal <sanjayl@kymasys.com>.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Sanjay Lal <sanjayl@kymasys.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
target-mips: Enable KVM support in build system

Enable KVM support for MIPS in the build system.

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
MAINTAINERS: Add entry for MIPS KVM

Add MAINTAINERS entry for MIPS KVM.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hw/mips: malta: Don't boot from flash with KVM T&E

In KVM trap & emulate (T&E) mode the flash reset region at 0xbfc00000
isn't executable, which is why the minimal kernel bootloader is loaded
and executed from the last 1MB of DRAM instead.

Therefore if no kernel is provided on the command line and KVM is
enabled, exit with an error since booting from flash will fail.

Reported-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Merge remote-tracking branch 'remotes/kvm/uq/master' into staging

* remotes/kvm/uq/master:
  hw/mips: malta: Don't boot from flash with KVM T&E
  MAINTAINERS: Add entry for MIPS KVM
  target-mips: Enable KVM support in build system
  hw/mips: malta: Add KVM support
  hw/mips: In KVM mode, inject IRQ2 (I/O) interrupts via ioctls
  target-mips: Call kvm_mips_reset_vcpu() from mips_cpu_reset()
  target-mips: kvm: Add main KVM support for MIPS
  kvm: Allow arch to set sigmask length
  target-mips: get_physical_address: Add KVM awareness
  target-mips: get_physical_address: Add defines for segment bases
  hw/mips: Add API to convert KVM guest KSEG0 <-> GPA
  hw/mips/cputimer: Don't start periodic timer in KVM mode
  target-mips: Reset CPU timer consistently
  KVM: Fix GSI number space limit

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>