When cr0.mp is clear, the guest doesn't expect a #NM in response to
a WAIT instruction. Because we always keep cr0.mp set, it will get
a #NM, and potentially be confused.
Fix by keeping cr0.mp set only when the fpu is inactive, and passing
it through when inactive.
Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Analyzed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
If we fail to alloc page for vcpu->arch.mmu.pae_root, call to
free_mmu_pages() is unnecessary, which just do free the page
malloc for vcpu->arch.mmu.pae_root.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
'mask' is always a constant, so we can check whether it includes a bit that
might be owned by the guest very cheaply, and avoid the decache call. Saves
a few hundred bytes of module text.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Assume that if the guest executes clts, it knows what it's doing, and load the
guest fpu to prevent an #NM exception.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This allows accessing the guest fpu from the instruction emulator, as well as
being symmetric with kvm_put_guest_fpu().
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Move to/from Control Registers chapter of Intel SDM says. "Reserved bits
in CR0 remain clear after any load of those registers; attempts to set
them have no impact". Control Register chapter says "Bits 63:32 of CR0 are
reserved and must be written with zeros. Writing a nonzero value to any
of the upper 32 bits results in a general-protection exception, #GP(0)."
This patch tries to implement this twisted logic.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
To enable proper debug register emulation under all conditions, trap
access to all DR0..7. This may be optimized later on.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Enhance mov dr instruction emulation used by SVM so that it properly
handles dr4/5: alias to dr6/7 if cr4.de is cleared. Otherwise return
EMULATE_FAIL which will let our only possible caller in that scenario,
ud_interception, re-inject UD.
We do not need to inject faults, SVM does this for us (exceptions take
precedence over instruction interceptions). For the same reason, the
value overflow checks can be removed.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
As we trap all debug register accesses, we do not need to switch real
DR6 at all. Clean up update_exception_bitmap at this chance, too.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Make sure DR4 and DR5 are aliased to DR6 and DR7, respectively, if
CR4.DE is not set.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo 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: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo 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: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@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: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
Windows issues this hypercall after guest was spinning on a spinlock
for too many iterations.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Vadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Provide HYPER-V related defines that will be used by following patches.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Vadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: Avi 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: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi 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: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi 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: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi 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: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi 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: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi 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: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo 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: Avi 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: Avi Kivity <avi@redhat.com>
The explanation of write_emulated is confused with
that of read_emulated. This patch fix it.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Then the callback can provide the maximum supported large page level, which
is more flexible.
Also move the gb page support into x86_64 specific.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Some exit reasons missed their strings; fill out the table.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
With slots_lock converted to rcu, the entire kvm hotpath on modern processors
(with npt or ept) now scales beautifully. Increase the maximum vcpu count to
64 to reflect this.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Use two steps for memslot deletion: mark the slot invalid (which stops
instantiation of new shadow pages for that slot, but allows destruction),
then instantiate the new empty slot.
Also simplifies kvm_handle_hva locking.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
