Injecting GP without an error code is a bad idea (causes unhandled guest
exits). Moreover, we must not skip the instruction if we injected an
exception.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

The return values from x86_emulate_ops are defined
in kvm_emulate.h as macros X86EMUL_*.

But in emulate.c, we are comparing the return values
from these ops with 0 to check if they're X86EMUL_CONTINUE
or not: X86EMUL_CONTINUE is defined as 0 now.

To avoid possible mistakes in the future, this patch
substitutes "X86EMUL_CONTINUE" for "0" that are being
compared with the return values from x86_emulate_ops.

  We think that there are more places we should use these
  macros, but the meanings of rc values in x86_emulate_insn()
  were not so clear at a glance. If we use proper macros in
  this function, we would be able to follow the flow of each
  emulation more easily and, maybe, more securely.
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

cleanup_srcu_struct on VM destruction remains broken:

BUG: unable to handle kernel paging request at ffffffffffffffff
IP: [<ffffffff802533d2>] srcu_read_lock+0x16/0x21
RIP: 0010:[<ffffffff802533d2>]  [<ffffffff802533d2>] srcu_read_lock+0x16/0x21
Call Trace:
 [<ffffffffa05354c4>] kvm_arch_vcpu_uninit+0x1b/0x48 [kvm]
 [<ffffffffa05339c6>] kvm_vcpu_uninit+0x9/0x15 [kvm]
 [<ffffffffa0569f7d>] vmx_free_vcpu+0x7f/0x8f [kvm_intel]
 [<ffffffffa05357b5>] kvm_arch_destroy_vm+0x78/0x111 [kvm]
 [<ffffffffa053315b>] kvm_put_kvm+0xd4/0xfe [kvm]

Move it to kvm_arch_destroy_vm.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Reported-by: NJan Kiszka <jan.kiszka@siemens.com>

Fix compilation warnings and wrong mask value.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

As Avi noted:

>There are two problems with the kernel failure report.  First, it
>doesn't report enough data - registers, surrounding instructions, etc.
>that are needed to explain what is going on.  Second, it can flood
>dmesg, which is a pretty bad thing to do.

So we remove the emulation failure report in handle_invalid_guest_state(),
and would inspected the guest using userspace tool in the future.
Signed-off-by: NSheng Yang <sheng@linux.intel.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Needed by <asm/kvm_para.h>.
Signed-off-by: NAvi Kivity <avi@redhat.com>

There are two spellings of "writable" in
arch/x86/kvm/mmu.c and paging_tmpl.h .

This patch renames is_writeble_pte() to is_writable_pte()
and makes grepping easy.

  New name is consistent with the definition of itself:
  return pte & PT_WRITABLE_MASK;
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Windows issues this hypercall after guest was spinning on a spinlock
for too many iterations.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NVadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Implement HYPER-V apic MSRs. Spec defines three MSRs that speed-up
access to EOI/TPR/ICR apic registers for PV guests.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NVadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Minimum HYPER-V implementation should have GUEST_OS_ID, HYPERCALL and
VP_INDEX MSRs.

[avi: fix build on i386]
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NVadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Provide HYPER-V related defines that will be used by following patches.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NVadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We keep a copy of the MSR around that we use when we go into the guest context.

That copy is basically the normal process MSR flags OR some allowed guest
specified MSR flags. We also AND the external providers into this, so we get
traps on FPU usage when we haven't activated it on the host yet.

Currently this calculation is part of the set_msr function that we use whenever
we set the guest MSR value. With the external providers, we also have the case
that we don't modify the guest's MSR, but only want to update the shadow MSR.

So let's move the shadow MSR parts to a separate function that we then use
whenever we only need to update it. That way we don't accidently kvm_vcpu_block
within a preempt notifier context.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

SRR1 stores more information that just the MSR value. It also stores
valuable information about the type of interrupt we received, for
example whether the storage interrupt we just got was because of a
missing htab entry or not.

We use that information to speed up the exit path.

Now if we get preempted before we can interpret the shadow_msr values,
we get into vcpu_put which then calls the MSR handler, which then sets
all the SRR1 information bits in shadow_msr to 0. Great.

So let's preserve the SRR1 specific bits in shadow_msr whenever we set
the MSR. They don't hurt.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Commit 7d01b4c3ed2bb33ceaf2d270cb4831a67a76b51b introduced PACA backed vcpu
values. With this patch, when a userspace app was setting GPRs before it was
actually first loaded, the set values get discarded.

This is because vcpu_load loads them from the vcpu backing store that we use
whenever we're not owning the PACA.

That behavior is not really a major problem, because we don't need it for
qemu. Other users (like kvmctl) do have problems with it though, so let's
better do it right.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

When our guest starts using either the FPU, Altivec or VSX we need to make
sure Linux knows about it and sneak into its process switching code
accordingly.

This patch makes accesses to the above parts of the system work inside the
VM.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Linux contains quite some bits of code to load FPU, Altivec and VSX lazily for
a task. It calls those bits in real mode, coming from an interrupt handler.

For KVM we better reuse those, so let's wrap a bit of trampoline magic around
them and then we can call them from normal module code.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We need to explicitly only giveup VSX in KVM, so let's export that
specific function to module space.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

kvm_get_exit_data() cannot return a NULL pointer.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Now that we can allow the guest to play with cr0 when the fpu is loaded,
we can enable lazy fpu when npt is in use.
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

If two conditions apply:
 - no bits outside TS and EM differ between the host and guest cr0
 - the fpu is active

then we can activate the selective cr0 write intercept and drop the
unconditional cr0 read and write intercept, and allow the guest to run
with the host fpu state.  This reduces cr0 exits due to guest fpu management
while the guest fpu is loaded.
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Currently we don't intercept cr0 at all when npt is enabled.  This improves
performance but requires us to activate the fpu at all times.

Remove this behaviour in preparation for adding selective cr0 intercepts.
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

init_vmcb() sets up the intercepts as if the fpu is active, so initialize it
there.  This avoids an INIT from setting up intercepts inconsistent with
fpu_active.
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Instead of selecting TS and MP as the comments say, the macro included TS and
PE.  Luckily the macro is unused now, but fix in order to save a few hours of
debugging from anyone who attempts to use it.
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Follow the hardware.
Signed-off-by: NAvi Kivity <avi@redhat.com>

If the guest fpu is loaded, there is nothing interesing about cr0.ts; let
the guest play with it as it will.  This makes context switches between fpu
intensive guest processes faster, as we won't trap the clts and cr0 write
instructions.

[marcelo: fix cr0 read shadow update on fpu deactivation; kills F8 install]
Signed-off-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Defer fpu deactivation as much as possible - if the guest fpu is loaded, keep
it loaded until the next heavyweight exit (where we are forced to unload it).
This reduces unnecessary exits.

We also defer fpu activation on clts; while clts signals the intent to use the
fpu, we can't be sure the guest will actually use it.
Signed-off-by: NAvi Kivity <avi@redhat.com>

We will use this later to give the guest ownership of cr0.ts.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Since we'd like to allow the guest to own a few bits of cr0 at times, we need
to know when we access those bits.
Signed-off-by: NAvi Kivity <avi@redhat.com>

clts writes cr0.ts; lmsw writes cr0[0:15] - record that in ftrace.
Signed-off-by: NAvi Kivity <avi@redhat.com>

An SLB entry contains two pieces of information related to size:

  1) PTE size
  2) SLB size

The L bit defines the PTE be "large" (usually means 16MB),
SLB_VSID_B_1T defines that the SLB should span 1 GB instead of the
default 256MB.

Apparently I messed things up and just put those two in one box,
shaked it heavily and came up with the current code which handles
large pages incorrectly, because it also treats large page SLB entries
as "1TB" segment entries.

This patch splits those two features apart, making Linux guests boot
even when they have > 256MB.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

When we get a program interrupt in guest kernel mode, we try to emulate the
instruction.

If that doesn't fail, we report to the user and try again - at the exact same
instruction pointer. So if the guest kernel really does trigger an invalid
instruction, we loop forever.

So let's better go and forward program exceptions to the guest when we don't
know the instruction we're supposed to emulate.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

When we need to reinject a program interrupt into the guest, we also need to
reinject the corresponding flags into the guest.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Reported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAvi Kivity <avi@redhat.com>

The code to unset HID5.dcbz32 is broken.
This patch makes it do the right rotate magic.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Reported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Book3S needs some flags in SRR1 to get to know details about an interrupt.

One such example is the trap instruction. It tells the guest kernel that
a program interrupt is due to a trap using a bit in SRR1.

This patch implements above behavior, making WARN_ON behave like WARN_ON.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Currently we're racy when doing the transition from IR=1 to IR=0, from
the module memory entry code to the real mode SLB switching code.

To work around that I took a look at the RTAS entry code which is faced
with a similar problem and did the same thing:

  A small helper in linear mapped memory that does mtmsr with IR=0 and
  then RFIs info the actual handler.

Thanks to that trick we can safely take page faults in the entry code
and only need to be really wary of what to do as of the SLB switching
part.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Using an RFI in IR=1 is dangerous. We need to set two SRRs and then do an RFI
without getting interrupted at all, because every interrupt could potentially
overwrite the SRR values.

Fortunately, we don't need to RFI in at least this particular case of the code,
so we can just replace it with an mtmsr and b.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

To fetch the last instruction we were interrupted on, we enable DR in early
exit code, where we are still in a very transitional phase between guest
and host state.

Most of the time this seemed to work, but another CPU can easily flush our
TLB and HTAB which makes us go in the Linux page fault handler which totally
breaks because we still use the guest's SLB entries.

To work around that, let's introduce a second KVM guest mode that defines
that whenever we get a trap, we don't call the Linux handler or go into
the KVM exit code, but just jump over the faulting instruction.

That way a potentially bad lwz doesn't trigger any faults and we can later
on interpret the invalid instruction we fetched as "fetch didn't work".
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We're being horribly racy right now. All the entry and exit code hijacks
random fields from the PACA that could easily be used by different code in
case we get interrupted, for example by a #MC or even page fault.

After discussing this with Ben, we figured it's best to reserve some more
space in the PACA and just shove off some vcpu state to there.

That way we can drastically improve the readability of the code, make it
less racy and less complex.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We now have helpers for the GPRs, so let's also add some for CR and XER.

Having them in the PACA simplifies code a lot, as we don't need to care
about where to store CC or not to overflow any integers.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

All code in PPC KVM currently accesses gprs in the vcpu struct directly.

While there's nothing wrong with that wrt the current way gprs are stored
and loaded, it doesn't suffice for the PACA acceleration that will follow
in this patchset.

So let's just create little wrapper inline functions that we call whenever
a GPR needs to be read from or written to. The compiled code shouldn't really
change at all for now.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>