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Preemption is disabled between kernel_fpu_begin/end() and as such
it is not a good idea to use these routines in kvm_load/put_guest_fpu()
which can be very far apart.
kvm_load/put_guest_fpu() routines are already called with
preemption disabled and KVM already uses the preempt notifier to save
the guest fpu state using kvm_put_guest_fpu().
So introduce __kernel_fpu_begin/end() routines which don't touch
preemption and use them instead of kernel_fpu_begin/end()
for KVM's use model of saving/restoring guest FPU state.
Also with this change (and with eagerFPU model), fix the host cr0.TS vm-exit
state in the case of VMX. For eagerFPU case, host cr0.TS is always clear.
So no need to worry about it. For the traditional lazyFPU restore case,
change the cr0.TS bit for the host state during vm-exit to be always clear
and cr0.TS bit is set in the __vmx_load_host_state() when the FPU
(guest FPU or the host task's FPU) state is not active. This ensures
that the host/guest FPU state is properly saved, restored
during context-switch and with interrupts (using irq_fpu_usable()) not
stomping on the active FPU state.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1348164109.26695.338.camel@sbsiddha-desk.sc.intel.com
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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Exporting KVM exit information to userspace to be consumed by perf.
Signed-off-by: Dong Hao <haodong@linux.vnet.ibm.com>
[ Dong Hao <haodong@linux.vnet.ibm.com>: rebase it on acme's git tree ]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1347870675-31495-2-git-send-email-haodong@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Most interrupt are delivered to only one vcpu. Use pre-build tables to
find interrupt destination instead of looping through all vcpus. In case
of logical mode loop only through vcpus in a logical cluster irq is sent
to.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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'ac' essentially reconstructs the 'access' variable we already
have, except for the PFERR_PRESENT_MASK and PFERR_RSVD_MASK. As
these are not used by callees, just use 'access' directly.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Keep track of accessed/dirty bits; if they are all set, do not
enter the accessed/dirty update loop.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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'eperm' is no longer used in the walker loop, so we can eliminate it.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Instead of branchy code depending on level, gpte.ps, and mmu configuration,
prepare everything in a bitmap during mode changes and look it up during
runtime.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The page table walk is coded as an infinite loop, with a special
case on the last pte.
Code it as an ordinary loop with a termination condition on the last
pte (large page or walk length exhausted), and put the last pte handling
code after the loop where it belongs.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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walk_addr_generic() permission checks are a maze of branchy code, which is
performed four times per lookup. It depends on the type of access, efer.nxe,
cr0.wp, cr4.smep, and in the near future, cr4.smap.
Optimize this away by precalculating all variants and storing them in a
bitmap. The bitmap is recalculated when rarely-changing variables change
(cr0, cr4) and is indexed by the often-changing variables (page fault error
code, pte access permissions).
The permission check is moved to the end of the loop, otherwise an SMEP
fault could be reported as a false positive, when PDE.U=1 but PTE.U=0.
Noted by Xiao Guangrong.
The result is short, branch-free code.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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While unspecified, the behaviour of Intel processors is to first
perform the page table walk, then, if the walk was successful, to
atomically update the accessed and dirty bits of walked paging elements.
While we are not required to follow this exactly, doing so will allow us
to perform the access permissions check after the walk is complete, rather
than after each walk step.
(the tricky case is SMEP: a zero in any pte's U bit makes the referenced
page a supervisor page, so we can't fault on a one bit during the walk
itself).
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We no longer rely on paging_tmpl.h defines; so we can move the function
to mmu.c.
Rely on zero extension to 64 bits to get the correct nx behaviour.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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If nx is disabled, then is gpte[63] is set we will hit a reserved
bit set fault before checking permissions; so we can ignore the
setting of efer.nxe.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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gpte_access() computes the access permissions of a guest pte and also
write-protects clean gptes. This is wrong when we are servicing a
write fault (since we'll be setting the dirty bit momentarily) but
correct when instantiating a speculative spte, or when servicing a
read fault (since we'll want to trap a following write in order to
set the dirty bit).
It doesn't seem to hurt in practice, but in order to make the code
readable, push the write protection out of gpte_access() and into
a new protect_clean_gpte() which is called explicitly when needed.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Found by http://coccinelle.lip6.fr/
Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Cc: avi@redhat.com
Cc: mtosatti@redhat.com
Cc: a.p.zijlstra@chello.nl
Cc: rusty@rustcorp.com.au
Cc: masami.hiramatsu.pt@hitachi.com
Cc: suresh.b.siddha@intel.com
Cc: joerg.roedel@amd.com
Cc: agordeev@redhat.com
Cc: yinghai@kernel.org
Cc: bhelgaas@google.com
Cc: liuj97@gmail.com
Link: http://lkml.kernel.org/r/1347986174-30287-7-git-send-email-peter.senna@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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kvm's guest fpu save/restore should be wrapped around
kernel_fpu_begin/end(). This will avoid for example taking a DNA
in kvm_load_guest_fpu() when it tries to load the fpu immediately
after doing unlazy_fpu() on the host side.
More importantly this will prevent the host process fpu from being
corrupted.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-4-git-send-email-suresh.b.siddha@intel.com
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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vcpu mutex can be held for unlimited time so
taking it with mutex_lock on an ioctl is wrong:
one process could be passed a vcpu fd and
call this ioctl on the vcpu used by another process,
it will then be unkillable until the owner exits.
Call mutex_lock_killable instead and return status.
Note: mutex_lock_interruptible would be even nicer,
but I am not sure all users are prepared to handle EINTR
from these ioctls. They might misinterpret it as an error.
Cleanup paths expect a vcpu that can't be used by
any userspace so this will always succeed - catch bugs
by calling BUG_ON.
Catch callers that don't check return state by adding
__must_check.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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Use macros for bitness-insensitive register names, instead of
rolling our own.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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Use macros for bitness-insensitive register names, instead of
rolling our own.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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LTO (link-time optimization) doesn't like local labels to be referred to
from a different function, since the two functions may be built in separate
compilation units. Use an external variable instead.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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find_highest_vector() and count_vectors():
- Instead of using magic values, define and use proper macros.
find_highest_vector():
- Remove likely() which is there only for historical reasons and not
doing correct branch predictions anymore. Using such heuristics
to optimize this function is not worth it now. Let CPUs predict
things instead.
- Stop checking word[0] separately. This was only needed for doing
likely() optimization.
- Use for loop, not while, to iterate over the register array to make
the code clearer.
Note that we actually confirmed that the likely() did wrong predictions
by inserting debug code.
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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This bug was triggered:
[ 4220.198458] BUG: unable to handle kernel paging request at fffffffffffffffe
[ 4220.203907] IP: [<ffffffff81104d85>] put_page+0xf/0x34
......
[ 4220.237326] Call Trace:
[ 4220.237361] [<ffffffffa03830d0>] kvm_arch_destroy_vm+0xf9/0x101 [kvm]
[ 4220.237382] [<ffffffffa036fe53>] kvm_put_kvm+0xcc/0x127 [kvm]
[ 4220.237401] [<ffffffffa03702bc>] kvm_vcpu_release+0x18/0x1c [kvm]
[ 4220.237407] [<ffffffff81145425>] __fput+0x111/0x1ed
[ 4220.237411] [<ffffffff8114550f>] ____fput+0xe/0x10
[ 4220.237418] [<ffffffff81063511>] task_work_run+0x5d/0x88
[ 4220.237424] [<ffffffff8104c3f7>] do_exit+0x2bf/0x7ca
The test case:
printf(fmt, ##args); \
exit(-1);} while (0)
static int create_vm(void)
{
int sys_fd, vm_fd;
sys_fd = open("/dev/kvm", O_RDWR);
if (sys_fd < 0)
die("open /dev/kvm fail.\n");
vm_fd = ioctl(sys_fd, KVM_CREATE_VM, 0);
if (vm_fd < 0)
die("KVM_CREATE_VM fail.\n");
return vm_fd;
}
static int create_vcpu(int vm_fd)
{
int vcpu_fd;
vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0);
if (vcpu_fd < 0)
die("KVM_CREATE_VCPU ioctl.\n");
printf("Create vcpu.\n");
return vcpu_fd;
}
static void *vcpu_thread(void *arg)
{
int vm_fd = (int)(long)arg;
create_vcpu(vm_fd);
return NULL;
}
int main(int argc, char *argv[])
{
pthread_t thread;
int vm_fd;
(void)argc;
(void)argv;
vm_fd = create_vm();
pthread_create(&thread, NULL, vcpu_thread, (void *)(long)vm_fd);
printf("Exit.\n");
return 0;
}
It caused by release kvm->arch.ept_identity_map_addr which is the
error page.
The parent thread can send KILL signal to the vcpu thread when it was
exiting which stops faulting pages and potentially allocating memory.
So gfn_to_pfn/gfn_to_page may fail at this time
Fixed by checking the page before it is used
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Checking the return of kvm_mmu_get_page is unnecessary since it is
guaranteed by memory cache
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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KVM lapic timer and tsc deadline timer based on hrtimer,
setting a leftmost node to rb tree and then do hrtimer reprogram.
If hrtimer not configured as high resolution, hrtimer_enqueue_reprogram
do nothing and then make kvm lapic timer and tsc deadline timer fail.
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Checks and operations on the INVPCID feature bit should use EBX
of CPUID leaf 7 instead of ECX.
Signed-off-by: Junjie Mao <junjie.mao@intel.com>
Signed-off-by: Yongjie Ren <yongjien.ren@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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interrupt_bitmap is KVM_NR_INTERRUPTS bits in size,
so just use that instead of hard-coded constants
and math.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Optimize "rep ins" by allowing emulator to write back more than one
datum at a time. Introduce new operand type OP_MEM_STR which tells
writeback() that dst contains pointer to an array that should be written
back as opposite to just one data element.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Remove unneeded segment argument. Address structure already has correct
segment which was put there during decode.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Current code assumes that IO exit was due to instruction emulation
and handles execution back to emulator directly. This patch adds new
userspace IO exit completion callback that can be set by any other code
that caused IO exit to userspace.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Other arches do not need this.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
v2: fix incorrect deletion of mmio sptes on gpa move (noticed by Takuya)
Signed-off-by: Avi Kivity <avi@redhat.com>
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Introducing kvm_arch_flush_shadow_memslot, to invalidate the
translations of a single memory slot.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We never modify direct_access_msrs[], msrpm_ranges[],
svm_exit_handlers[] or x86_intercept_map[] at runtime.
Mark them r/o.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We use vmcs_field_to_offset_table[], kvm_vmx_segment_fields[] and
kvm_vmx_exit_handlers[] as lookup tables only -- make them r/o.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We never change those, make them r/o.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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We never change emulate_ops[] at runtime so it should be r/o.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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The opcode tables never change at runtime, therefor mark them const.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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As the the compiler ensures that the memory operand is always aligned
to a 16 byte memory location, use the aligned variant of MOVDQ for
read_sse_reg() and write_sse_reg().
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Some fields can be constified and/or made static to reduce code and data
size.
Numbers for a 32 bit build:
text data bss dec hex filename
before: 3351 80 0 3431 d67 cpuid.o
after: 3391 0 0 3391 d3f cpuid.o
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Commit aea218f3cbbc (KVM: PIC: call ack notifiers for irqs that are
dropped form irr) used an uninitialised variable to track whether an
appropriate apic had been found. This could result in calling the ack
notifier incorrectly.
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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kvm_pic_reset() is not used anywhere. Move reset logic from
pic_ioport_write() there.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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We will enter the guest with G and D cleared; as real hardware ignores D in
real mode, and G is taken care of by the limit test, we allow more code to
run in vm86 mode.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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While this is undocumented, real processors do not reload the segment
limit and access rights when loading a segment register in real mode.
Real programs rely on it so we need to comply with this behaviour.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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emulate_invalid_guest_state=1
emulate_invalid_guest_state=1 doesn't mean we don't munge the segments in the
vmcs; we do. So we need to return the real ones (maintained by vmx_set_segment).
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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We want the segment selector, nor segment number.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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Segment limits are verified in real mode, not just protected mode.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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When loading a segment in real mode, only the base and selector must
be modified. The limit needs to be left alone, otherwise big real mode
users will hit a #GP due to limit checking (currently this is suppressed
because we don't check limits in real mode).
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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Usually, big real mode uses large (4GB) segments. Currently we don't
virtualize this; if any segment has a limit other than 0xffff, we emulate.
But if we set the vmx-visible limit to 0xffff, we can use vm86 to virtualize
real mode; if an access overruns the segment limit, the guest will #GP, which
we will trap and forward to the emulator. This results in significantly
faster execution, and less risk of hitting an unemulated instruction.
If the limit is less than 0xffff, we retain the existing behaviour.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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