This patch adds an implementation to the svm is_disabled function to
detect reliably if the BIOS disabled the SVM feature in the CPU. This
fixes the issues with kernel panics when loading the kvm-amd module on
machines where SVM is available but disabled.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

A vmexit implicitly flushes the tlb; the code is bogus.

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

Need to flush the tlb after updating a pte, not before.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Protected mode code may have corrupted the real-mode tss, so re-initialize
it when switching to real mode.
Signed-off-by: Avi Kivity <avi@qumranet.com>

When writing to normal memory and the memory area is unchanged the write
can be safely skipped, avoiding the costly kvm_mmu_pte_write.
Signed-Off-By: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

When the old value and new one are the same the emulator skips the
write; this is undesirable when the destination is a MMIO area and the
write shall be performed regardless of the previous value. This
optimization breaks e.g. a Linux guest APIC compiled without
X86_GOOD_APIC.

Remove the check and perform the writeback stage in the emulation unless
it's explicitly disabled (currently push and some 2 bytes instructions
may disable the writeback).
Signed-Off-By: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Useful for the PIC and PIT.
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

With kernel-injected interrupts, we need to check for interrupts on
lightweight exits too.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

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>