Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

For use in real mode.
Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

If the time stamp counter goes backwards, a guest delay loop can become
infinite.  This can happen if a vcpu is migrated to another cpu, where
the counter has a lower value than the first cpu.

Since we're doing an IPI to the first cpu anyway, we can use that to pick
up the old tsc, and use that to calculate the adjustment we need to make
to the tsc offset.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Needs to be set on vcpu 0 only.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Shani Moideen <shani.moideen@wipro.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Shani Moideen <shani.moideen@wipro.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

When a vcpu causes a shadow tlb entry to have reduced permissions, it
must also clear the tlb on remote vcpus.  We do that by:

- setting a bit on the vcpu that requests a tlb flush before the next entry
- if the vcpu is currently executing, we send an ipi to make sure it
  exits before we continue
Signed-off-by: Avi Kivity <avi@qumranet.com>

That way, we don't need to loop for KVM_MAX_VCPUS for a single vcpu
vm.
Signed-off-by: Avi Kivity <avi@qumranet.com>

This has two use cases: the bios can't boot from disk, and guest smp
bootstrap.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Will soon have a thid user.
Signed-off-by: Avi Kivity <avi@qumranet.com>

As we don't support guest tlb shootdown yet, this is only reliable
for real-mode guests.
Signed-off-by: Avi Kivity <avi@qumranet.com>

If we add the vm once per vcpu, we corrupt the list if the guest has
multiple vcpus.
Signed-off-by: Avi Kivity <avi@qumranet.com>

A vcpu can pin up to four mmu shadow pages, which means the freeing
loop will never terminate.  Fix by first unpinning shadow pages on
all vcpus, then freeing shadow pages.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Switch guest paging context may require us to allocate memory, which
might fail.  Instead of wiring up error paths everywhere, make context
switching lazy and actually do the switch before the next guest entry,
where we can return an error if allocation fails.
Signed-off-by: Avi Kivity <avi@qumranet.com>

This has not been used for some time, as the same information is available
in the page header.
Signed-off-by: Avi Kivity <avi@qumranet.com>

This was once used to avoid accessing the guest pte when upgrading
the shadow pte from read-only to read-write.  But usually we need
to set the guest pte dirty or accessed bits anyway, so this wasn't
really exploited.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Always set the accessed and dirty bit (since having them cleared causes
a read-modify-write cycle), always set the present bit, and copy the
nx bit from the guest.
Signed-off-by: Avi Kivity <avi@qumranet.com>

No longer needed as we do everything in one place.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Avi Kivity <avi@qumranet.com>

With guest smp, a second vcpu might see partial updates when the first
vcpu services a page fault.  So delay all updates until we have figured
out what the pte should look like.

Note that on i386, this is still not completely atomic as a 64-bit write
will be split into two on a 32-bit machine.
Signed-off-by: Avi Kivity <avi@qumranet.com>

We want all shadow pte modifications in one place.
Signed-off-by: Avi Kivity <avi@qumranet.com>

This prevents some work from being performed twice, and, more importantly,
reduces the number of places where we modify shadow ptes.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Avi Kivity <avi@qumranet.com>

We will need the accessed bit (in addition to the dirty bit) and
also write access (for setting the dirty bit) in a future patch.
Signed-off-by: Avi Kivity <avi@qumranet.com>

In preparation of some modifications.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Avi Kivity <avi@qumranet.com>

Use slab caches instead of a simple custom list.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Avi Kivity <avi@qumranet.com>

KVM compilation fails for some .configs.  This fixes it.
Signed-off-by: Markus Rechberger <markus.rechberger@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Vista seems to trigger it.
Signed-off-by: Avi Kivity <avi@qumranet.com>

Make a "menuconfig" out of the Kconfig objects "menu, ..., endmenu",
so that the user can disable all the options in that menu at once
instead of having to disable each option separately.
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>

MSR_EFER.LME/LMA bits are automatically save/restored by VMX
hardware, KVM only needs to save NX/SCE bits at time of heavy
weight VM Exit. But clearing NX bits in host envirnment may
cause system hang if the host page table is using EXB bits,
thus we leave NX bits as it is. If Host NX=1 and guest NX=0, we
can do guest page table EXB bits check before inserting a shadow
pte (though no guest is expecting to see this kind of gp fault).
If host NX=0, we present guest no Execute-Disable feature to guest,
thus no host NX=0, guest NX=1 combination.

This patch reduces raw vmexit time by ~27%.

Me: fix compile warnings on i386.
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

In a lightweight exit (where we exit and reenter the guest without
scheduling or exiting to userspace in between), we don't need various
msrs on the host, and avoiding shuffling them around reduces raw exit
time by 8%.

i386 compile fix by Daniel Hecken <dh@bahntechnik.de>.
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Instructions with address size override prefix opcode 0x67
Cause the #SS fault with 0 error code in VM86 mode.  Forward
them to the emulator.
Signed-Off-By: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

This makes oprofile dumps and disassebly easier to read.
Signed-off-by: Avi Kivity <avi@qumranet.com>

kunmap() expects a struct page, not a virtual address.  Fixes an oops loading
kvm-intel.ko on i386 with CONFIG_HIGHMEM.

Thanks to Michael Ivanov <deruhu@peterstar.ru> for reporting.
Signed-off-by: Avi Kivity <avi@qumranet.com>

The real mode tr needs to be set to a specific tss so that I/O
instructions can function.  Divert the new tr values to the real
mode save area from where they will be restored on transition to
protected mode.

This fixes some crashes on reboot when the bios accesses an I/O
instruction.
Signed-off-by: Avi Kivity <avi@qumranet.com>