Commit Graph

9 Commits

Author SHA1 Message Date
Marc Zyngier af20814ee9 ARM: KVM: add world-switch for AMAIR{0,1}
HCR.TVM traps (among other things) accesses to AMAIR0 and AMAIR1.
In order to minimise the amount of surprise a guest could generate by
trying to access these registers with caches off, add them to the
list of registers we switch/handle.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
2014-03-03 01:15:24 +00:00
Marc Zyngier ac30a11e8e ARM: KVM: introduce per-vcpu HYP Configuration Register
So far, KVM/ARM used a fixed HCR configuration per guest, except for
the VI/VF/VA bits to control the interrupt in absence of VGIC.

With the upcoming need to dynamically reconfigure trapping, it becomes
necessary to allow the HCR to be changed on a per-vcpu basis.

The fix here is to mimic what KVM/arm64 already does: a per vcpu HCR
field, initialized at setup time.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
2014-03-03 01:15:23 +00:00
Linus Torvalds fe489bf450 KVM fixes for 3.11
On the x86 side, there are some optimizations and documentation updates.
 The big ARM/KVM change for 3.11, support for AArch64, will come through
 Catalin Marinas's tree.  s390 and PPC have misc cleanups and bugfixes.
 
 There is a conflict due to "s390/pgtable: fix ipte notify bit" having
 entered 3.10 through Martin Schwidefsky's s390 tree.  This pull request
 has additional changes on top, so this tree's version is the correct one.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "On the x86 side, there are some optimizations and documentation
  updates.  The big ARM/KVM change for 3.11, support for AArch64, will
  come through Catalin Marinas's tree.  s390 and PPC have misc cleanups
  and bugfixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (87 commits)
  KVM: PPC: Ignore PIR writes
  KVM: PPC: Book3S PR: Invalidate SLB entries properly
  KVM: PPC: Book3S PR: Allow guest to use 1TB segments
  KVM: PPC: Book3S PR: Don't keep scanning HPTEG after we find a match
  KVM: PPC: Book3S PR: Fix invalidation of SLB entry 0 on guest entry
  KVM: PPC: Book3S PR: Fix proto-VSID calculations
  KVM: PPC: Guard doorbell exception with CONFIG_PPC_DOORBELL
  KVM: Fix RTC interrupt coalescing tracking
  kvm: Add a tracepoint write_tsc_offset
  KVM: MMU: Inform users of mmio generation wraparound
  KVM: MMU: document fast invalidate all mmio sptes
  KVM: MMU: document fast invalidate all pages
  KVM: MMU: document fast page fault
  KVM: MMU: document mmio page fault
  KVM: MMU: document write_flooding_count
  KVM: MMU: document clear_spte_count
  KVM: MMU: drop kvm_mmu_zap_mmio_sptes
  KVM: MMU: init kvm generation close to mmio wrap-around value
  KVM: MMU: add tracepoint for check_mmio_spte
  KVM: MMU: fast invalidate all mmio sptes
  ...
2013-07-03 13:21:40 -07:00
Marc Zyngier 6a077e4ab9 ARM: KVM: perform save/restore of PAR
Not saving PAR is an unfortunate oversight. If the guest performs
an AT* operation and gets scheduled out before reading the result
of the translation from PAR, it could become corrupted by another
guest or the host.

Saving this register is made slightly more complicated as KVM also
uses it on the permission fault handling path, leading to an ugly
"stash and restore" sequence. Fortunately, this is already a slow
path so we don't really care. Also, Linux doesn't do any AT*
operation, so Linux guests are not impacted by this bug.

  [ Slightly tweaked to use an even register as first operand to ldrd
    and strd operations in interrupts_head.S - Christoffer ]

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2013-06-26 10:50:04 -07:00
Mark Rutland f793c23ebb ARM: KVM: arch_timers: zero CNTVOFF upon return to host
To use the virtual counters from the host, we need to ensure that
CNTVOFF doesn't change unexpectedly. When we change to a guest, we
replace the host's CNTVOFF, but we don't restore it when returning to
the host.

As the host sets CNTVOFF to zero, and never changes it, we can simply
zero CNTVOFF when returning to the host. This patch adds said zeroing to
the return to host path.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Christoffer Dall <cdall@cs.columbia.edu>
2013-06-07 10:20:27 +01:00
Marc Zyngier c7e3ba64ba ARM: KVM: arch_timers: Add timer world switch
Do the necessary save/restore dance for the timers in the world
switch code. In the process, allow the guest to read the physical
counter, which is useful for its own clock_event_device.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-02-11 19:05:38 +00:00
Marc Zyngier 53e724067a ARM: KVM: arch_timers: Add guest timer core support
Add some the architected timer related infrastructure, and support timer
interrupt injection, which can happen as a resultof three possible
events:

- The virtual timer interrupt has fired while we were still
  executing the guest
- The timer interrupt hasn't fired, but it expired while we
  were doing the world switch
- A hrtimer we programmed earlier has fired

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-02-11 19:05:11 +00:00
Marc Zyngier 348b2b0708 ARM: KVM: VGIC control interface world switch
Enable the VGIC control interface to be save-restored on world switch.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-02-11 19:00:03 +00:00
Christoffer Dall f7ed45be3b KVM: ARM: World-switch implementation
Provides complete world-switch implementation to switch to other guests
running in non-secure modes. Includes Hyp exception handlers that
capture necessary exception information and stores the information on
the VCPU and KVM structures.

The following Hyp-ABI is also documented in the code:

Hyp-ABI: Calling HYP-mode functions from host (in SVC mode):
   Switching to Hyp mode is done through a simple HVC #0 instruction. The
   exception vector code will check that the HVC comes from VMID==0 and if
   so will push the necessary state (SPSR, lr_usr) on the Hyp stack.
   - r0 contains a pointer to a HYP function
   - r1, r2, and r3 contain arguments to the above function.
   - The HYP function will be called with its arguments in r0, r1 and r2.
   On HYP function return, we return directly to SVC.

A call to a function executing in Hyp mode is performed like the following:

        <svc code>
        ldr     r0, =BSYM(my_hyp_fn)
        ldr     r1, =my_param
        hvc #0  ; Call my_hyp_fn(my_param) from HYP mode
        <svc code>

Otherwise, the world-switch is pretty straight-forward. All state that
can be modified by the guest is first backed up on the Hyp stack and the
VCPU values is loaded onto the hardware. State, which is not loaded, but
theoretically modifiable by the guest is protected through the
virtualiation features to generate a trap and cause software emulation.
Upon guest returns, all state is restored from hardware onto the VCPU
struct and the original state is restored from the Hyp-stack onto the
hardware.

SMP support using the VMPIDR calculated on the basis of the host MPIDR
and overriding the low bits with KVM vcpu_id contributed by Marc Zyngier.

Reuse of VMIDs has been implemented by Antonios Motakis and adapated from
a separate patch into the appropriate patches introducing the
functionality. Note that the VMIDs are stored per VM as required by the ARM
architecture reference manual.

To support VFP/NEON we trap those instructions using the HPCTR. When
we trap, we switch the FPU.  After a guest exit, the VFP state is
returned to the host.  When disabling access to floating point
instructions, we also mask FPEXC_EN in order to avoid the guest
receiving Undefined instruction exceptions before we have a chance to
switch back the floating point state.  We are reusing vfp_hard_struct,
so we depend on VFPv3 being enabled in the host kernel, if not, we still
trap cp10 and cp11 in order to inject an undefined instruction exception
whenever the guest tries to use VFP/NEON. VFP/NEON developed by
Antionios Motakis and Rusty Russell.

Aborts that are permission faults, and not stage-1 page table walk, do
not report the faulting address in the HPFAR.  We have to resolve the
IPA, and store it just like the HPFAR register on the VCPU struct. If
the IPA cannot be resolved, it means another CPU is playing with the
page tables, and we simply restart the guest.  This quirk was fixed by
Marc Zyngier.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
2013-01-23 13:29:12 -05:00