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  1. 24 Mar, 2009 15 commits
    • Jan Kiszka's avatar
      KVM: x86: Virtualize debug registers · 42dbaa5a
      Jan Kiszka authored 
      So far KVM only had basic x86 debug register support, once introduced to
realize guest debugging that way. The guest itself was not able to use
those registers.

This patch now adds (almost) full support for guest self-debugging via
hardware registers. It refactors the code, moving generic parts out of
SVM (VMX was already cleaned up by the KVM_SET_GUEST_DEBUG patches), and
it ensures that the registers are properly switched between host and
guest.

This patch also prepares debug register usage by the host. The latter
will (once wired-up by the following patch) allow for hardware
breakpoints/watchpoints in guest code. If this is enabled, the guest
will only see faked debug registers without functionality, but with
content reflecting the guest's modifications.

Tested on Intel only, but SVM /should/ work as well, but who knows...

Known limitations: Trapping on tss switch won't work - most probably on
Intel.

Credits also go to Joerg Roedel - I used his once posted debugging
series as platform for this patch.
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      42dbaa5a
    • Jan Kiszka's avatar
      KVM: VMX: Allow single-stepping when uninterruptible · 55934c0b
      Jan Kiszka authored 
      When single-stepping over STI and MOV SS, we must clear the
corresponding interruptibility bits in the guest state. Otherwise
vmentry fails as it then expects bit 14 (BS) in pending debug exceptions
being set, but that's not correct for the guest debugging case.

Note that clearing those bits is safe as we check for interruptibility
based on the original state and do not inject interrupts or NMIs if
guest interruptibility was blocked.
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      55934c0b
    • Jan Kiszka's avatar
      KVM: New guest debug interface · d0bfb940
      Jan Kiszka authored 
      This rips out the support for KVM_DEBUG_GUEST and introduces a new IOCTL
instead: KVM_SET_GUEST_DEBUG. The IOCTL payload consists of a generic
part, controlling the "main switch" and the single-step feature. The
arch specific part adds an x86 interface for intercepting both types of
debug exceptions separately and re-injecting them when the host was not
interested. Moveover, the foundation for guest debugging via debug
registers is layed.

To signal breakpoint events properly back to userland, an arch-specific
data block is now returned along KVM_EXIT_DEBUG. For x86, the arch block
contains the PC, the debug exception, and relevant debug registers to
tell debug events properly apart.

The availability of this new interface is signaled by
KVM_CAP_SET_GUEST_DEBUG. Empty stubs for not yet supported archs are
provided.

Note that both SVM and VTX are supported, but only the latter was tested
yet. Based on the experience with all those VTX corner case, I would be
fairly surprised if SVM will work out of the box.
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      d0bfb940
    • Jan Kiszka's avatar
      KVM: VMX: Support for injecting software exceptions · 8ab2d2e2
      Jan Kiszka authored 
      VMX differentiates between processor and software generated exceptions
when injecting them into the guest. Extend vmx_queue_exception
accordingly (and refactor related constants) so that we can use this
service reliably for the new guest debugging framework.
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      8ab2d2e2
    • Alexander Graf's avatar
      KVM: SVM: Only allow setting of EFER_SVME when CPUID SVM is set · d8017474
      Alexander Graf authored 
      Userspace has to tell the kernel module somehow that nested SVM should be used.
The easiest way that doesn't break anything I could think of is to implement

if (cpuid & svm)
    allow write to efer
else
    deny write to efer

Old userspaces mask the SVM capability bit, so they don't break.
In order to find out that the SVM capability is set, I had to split the
kvm_emulate_cpuid into a finding and an emulating part.

(introduced in v6)
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      d8017474
    • Alexander Graf's avatar
      KVM: SVM: Allow setting the SVME bit · 236de055
      Alexander Graf authored 
      Normally setting the SVME bit in EFER is not allowed, as we did
not support SVM. Not since we do, we should also allow enabling
SVM mode.

v2 comes as last patch, so we don't enable half-ready code
v4 introduces a module option to enable SVM
v6 warns that nesting is enabled
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      236de055
    • Joerg Roedel's avatar
      KVM: SVM: Allow read access to MSR_VM_VR · eb6f302e
      Joerg Roedel authored 
      KVM tries to read the VM_CR MSR to find out if SVM was disabled by
the BIOS. So implement read support for this MSR to make nested
SVM running.
Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      eb6f302e
    • Alexander Graf's avatar
      KVM: SVM: Add VMEXIT handler and intercepts · cf74a78b
      Alexander Graf authored 
      This adds the #VMEXIT intercept, so we return to the level 1 guest
when something happens in the level 2 guest that should return to
the level 1 guest.

v2 implements HIF handling and cleans up exception interception
v3 adds support for V_INTR_MASKING_MASK
v4 uses the host page hsave
v5 removes IOPM merging code
v6 moves mmu code out of the atomic section
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      cf74a78b
    • Alexander Graf's avatar
      KVM: SVM: Add VMRUN handler · 3d6368ef
      Alexander Graf authored 
      This patch implements VMRUN. VMRUN enters a virtual CPU and runs that
in the same context as the normal guest CPU would run.
So basically it is implemented the same way, a normal CPU would do it.

We also prepare all intercepts that get OR'ed with the original
intercepts, as we do not allow a level 2 guest to be intercepted less
than the first level guest.

v2 implements the following improvements:

- fixes the CPL check
- does not allocate iopm when not used
- remembers the host's IF in the HIF bit in the hflags

v3:

- make use of the new permission checking
- add support for V_INTR_MASKING_MASK

v4:

- use host page backed hsave

v5:

- remove IOPM merging code

v6:

- save cr4 so PAE l1 guests work

v7:

- return 0 on vmrun so we check the MSRs too
- fix MSR check to use the correct variable
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      3d6368ef
    • Alexander Graf's avatar
      KVM: SVM: Add VMLOAD and VMSAVE handlers · 5542675b
      Alexander Graf authored 
      This implements the VMLOAD and VMSAVE instructions, that usually surround
the VMRUN instructions. Both instructions load / restore the same elements,
so we only need to implement them once.

v2 fixes CPL checking and replaces memcpy by assignments
v3 makes use of the new permission checking
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      5542675b
    • Alexander Graf's avatar
      KVM: SVM: Implement hsave · b286d5d8
      Alexander Graf authored 
      Implement the hsave MSR, that gives the VCPU a GPA to save the
old guest state in.

v2 allows userspace to save/restore hsave
v4 dummys out the hsave MSR, so we use a host page
v6 remembers the guest's hsave and exports the MSR
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      b286d5d8
    • Alexander Graf's avatar
      KVM: SVM: Implement GIF, clgi and stgi · 1371d904
      Alexander Graf authored 
      This patch implements the GIF flag and the clgi and stgi instructions that
set this flag. Only if the flag is set (default), interrupts can be received by
the CPU.

To keep the information about that somewhere, this patch adds a new hidden
flags vector. that is used to store information that does not go into the
vmcb, but is SVM specific.

I tried to write some code to make -no-kvm-irqchip work too, but the first
level guest won't even boot with that atm, so I ditched it.

v2 moves the hflags to x86 generic code
v3 makes use of the new permission helper
v6 only enables interrupt_window if GIF=1
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      1371d904
    • Alexander Graf's avatar
      KVM: SVM: Add helper functions for nested SVM · c0725420
      Alexander Graf authored 
      These are helpers for the nested SVM implementation.

- nsvm_printk implements a debug printk variant
- nested_svm_do calls a handler that can accesses gpa-based memory

v3 makes use of the new permission checker
v6 changes:
- streamline nsvm_debug()
- remove printk(KERN_ERR)
- SVME check before CPL check
- give GP error code
- use new EFER constant
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      c0725420
    • Alexander Graf's avatar
      KVM: SVM: Move EFER and MSR constants to generic x86 code · 9962d032
      Alexander Graf authored 
      MSR_EFER_SVME_MASK, MSR_VM_CR and MSR_VM_HSAVE_PA are set in KVM
specific headers. Linux does have nice header files to collect
EFER bits and MSR IDs, so IMHO we should put them there.

While at it, I also changed the naming scheme to match that
of the other defines.

(introduced in v6)
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      9962d032
    • Alexander Graf's avatar
      KVM: SVM: Clean up VINTR setting · f0b85051
      Alexander Graf authored 
      The current VINTR intercept setters don't look clean to me. To make
the code easier to read and enable the possibilty to trap on a VINTR
set, this uses a helper function to set the VINTR intercept.

v2 uses two distinct functions for setting and clearing the bit
Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
      f0b85051
  3. 23 Mar, 2009 11 commits
  5. 22 Mar, 2009 6 commits
  7. 21 Mar, 2009 2 commits
  9. 20 Mar, 2009 5 commits
  11. 19 Mar, 2009 1 commit
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