The general documentation we have for pv_ops is currenty present
on the IA64 docs, but since this documentation covers IA64 xen
enablement and IA64 Xen support got ripped out a while ago
through commit d52eefb4 present since v3.14-rc1 lets just
simplify, generalize and move the pv_ops documentation to a
shared place.

Cc: Isaku Yamahata <yamahata@valinux.co.jp>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: virtualization@lists.linux-foundation.org
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: xen-devel@lists.xenproject.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Disappointing, as this was kind of neat (especially getting to use RCU
to manage the address -> eventfd mapping).  But now the devices are PCI
handled in userspace, we get rid of both the NOTIFY hypercall and
the interface to connect an eventfd.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This was only used for early console, now we can get rid of it altogether.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This involves manually checking the console device (which is always in
slot 1 of bus 0) and using the window in VIRTIO_PCI_CAP_PCI_CFG to
program it (as we can't map the BAR yet).

We could in fact do this much earlier, but we wait for the first
write from the virtio_cons_early_init() facility.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This simplifies the early probe.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

The VIRTIO_PCI_CAP_PCI_CFG in the PCI virtio 1.0 spec allows access to
the BAR registers without mapping them.  This is a compulsory feature,
and we implement it here.

There are some subtleties involving access widths which we should
note:

4.1.4.7.1 Device Requirements: PCI configuration access capability

...
   Upon detecting driver write access to pci_cfg_data, the device MUST
   execute a write access at offset cap.offset at BAR selected by
   cap.bar using the first cap.length bytes from pci_cfg_data.

   Upon detecting driver read access to pci_cfg_data, the device MUST
   execute a read access of length cap.length at offset cap.offset at
   BAR selected by cap.bar and store the first cap.length bytes in
   pci_cfg_data.

So, for a write, we copy into the pci_cfg_data window, then write from
there out to the BAR.  This works correctly if cap.length != width of
write.  Similarly, for a read, we read into window from the BAR then
read the value from there.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This is a magic register which causes a character to be outputted: it can
be used even before the device is configured.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

The demonstration launcher now uses PCI entirely.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We only support virtio 1.0 now
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

The only real change here (other than using the PCI bus) is that we
didn't negotiate VIRTIO_NET_F_MRG_RXBUF before, so the format of the
packet header changed with virtio 1.0; we need TUNSETVNETHDRSZ on the
tun fd to tell it about the extra two bytes.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We remove SCSI support (which was removed for 1.0) and VIRTIO_BLK_F_FLUSH
feature flag (removed too, since it's compulsory for 1.0).

The rest is mainly mechanical.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Otherwise Linux fails to find the bus.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We want to use the local kernel headers, but -I../../include/uapi leads us into
a world of hurt.  Instead we create a dummy include/ dir with symlinks.

If we just use #include "../../include/uapi/linux/virtio_blk.h" we get:

	../../include/uapi/linux/virtio_blk.h:31:32: fatal error: linux/virtio_types.h: No such file or directory
	 #include <linux/virtio_types.h>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

For each device, We need to include the vendor capabilities to demark
where virtio common, notification and ISR regions are (we put them
all in BAR0).

We need to handle the switching of the virtqueues using the accessors.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This handles ioport 0xCF8 and 0xCFC accesses, which are used to
read/write PCI device config space.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We don't do anything with them yet (emulate_mmio_write and
emulate_mmio_read are stubs), but we decode the instructions and
search for the device they're hitting.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This is where we point our PCI BARs, so that we can intercept MMIO
accesses.  We tell the kernel about it so any faults in this area are
directed to us.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This lets us deliver interrupts for our emulated PCI devices using our
dumb PIC, and not emulate an 8259 and PCI irq mapping tables or whatever.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Once we add PCI, it starts trying to manage our interrupts.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This lets us implement PCI.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This no longer speeds up boot (IDE got better, I guess), but it does stop
us probing for a PCI bus.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

While hacking on getting I/O out to the lguest launcher, I noticed
that returning 0xFF for the PS/2 keyboard status made it spin for a
while thinking there was a key pending.  Fix this by returning 1
instead of 0xFF.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We copy 7 bytes at eip for userspace's instruction decode; we have to
carefully handle the case where eip is at the end of a page.  We can't
leave this to userspace since kernel has all the page table decode
logic.

The decode logic moves to userspace, basically unchanged.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We normally abort the guest unconditionally when it gives us a bad address,
but in the next patch we want to copy some bytes which may not be mapped.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This is required for instruction emulation to move to userspace.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This is preparation for userspace handling MMIO and ioport accesses.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We use the ptrace API struct, and we currently don't let them set
anything but the normal registers (we'd have to filter the others).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Theoretical debates aside, now it boots.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Strictly, it's only needed when we have features (size or multiport).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Since PCI is little endian, 8-bit access might work, but the spec section
is very clear on this:

  4.1.3.1 Driver Requirements: PCI Device Layout

  The driver MUST access each field using the “natural” access method,
  i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for 16-bit
  fields and 8-bit accesses for 8-bit fields.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

The VIRTIO_F_ANY_LAYOUT and VIRTIO_F_NOTIFY_ON_EMPTY features are pre-1.0
only.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

This allows modern implementations to ensure they don't use legacy
feature bits or SCSI commands (which are not used in v1.0 non-legacy).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

This provides backdoor access to the device MMIOs, and every device should
have one.  From the virtio 1.0 spec (CS03):

  4.1.4.7.1 Device Requirements: PCI configuration access capability

  The device MUST present at least one VIRTIO_PCI_CAP_PCI_CFG capability.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

The virtqueue_add() calls START_USE() upon entry. The virtqueue_kick() is
called if vq->num_added == (1 << 16) - 1 before calling END_USE().
The virtqueue_kick_prepare() called via virtqueue_kick() calls START_USE()
upon entry, and will call panic() if DEBUG is enabled.
Move this virtqueue_kick() call to after END_USE() call.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This patch add a support for second version of the virtio-mmio device,
which follows OASIS "Virtual I/O Device (VIRTIO) Version 1.0"
specification.

Main changes:

1. The control register symbolic names use the new device/driver
   nomenclature rather than the old guest/host one.

2. The driver detect the device version (version 1 is the pre-OASIS
   spec, version 2 is compatible with fist revision of the OASIS spec)
   and drives the device accordingly.

3. New version uses direct addressing (64 bit address split into two
   low/high register) instead of the guest page size based one,
   and addresses each part of the queue (descriptors, available, used)
   separately.

4. The device activity is now explicitly triggered by writing to the
   "queue ready" register.

5. Whole 64 bit features are properly handled now (both ways).
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

release function in modern driver is unused:
it's a left-over from when each driver had
to have its own release.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>