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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 12:43:55 +08:00
linux-next/arch/powerpc
David Gibson 99342cf804 kvmppc: Implement H_LOGICAL_CI_{LOAD,STORE} in KVM
On POWER, storage caching is usually configured via the MMU - attributes
such as cache-inhibited are stored in the TLB and the hashed page table.

This makes correctly performing cache inhibited IO accesses awkward when
the MMU is turned off (real mode).  Some CPU models provide special
registers to control the cache attributes of real mode load and stores but
this is not at all consistent.  This is a problem in particular for SLOF,
the firmware used on KVM guests, which runs entirely in real mode, but
which needs to do IO to load the kernel.

To simplify this qemu implements two special hypercalls, H_LOGICAL_CI_LOAD
and H_LOGICAL_CI_STORE which simulate a cache-inhibited load or store to
a logical address (aka guest physical address).  SLOF uses these for IO.

However, because these are implemented within qemu, not the host kernel,
these bypass any IO devices emulated within KVM itself.  The simplest way
to see this problem is to attempt to boot a KVM guest from a virtio-blk
device with iothread / dataplane enabled.  The iothread code relies on an
in kernel implementation of the virtio queue notification, which is not
triggered by the IO hcalls, and so the guest will stall in SLOF unable to
load the guest OS.

This patch addresses this by providing in-kernel implementations of the
2 hypercalls, which correctly scan the KVM IO bus.  Any access to an
address not handled by the KVM IO bus will cause a VM exit, hitting the
qemu implementation as before.

Note that a userspace change is also required, in order to enable these
new hcall implementations with KVM_CAP_PPC_ENABLE_HCALL.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[agraf: fix compilation]
Signed-off-by: Alexander Graf <agraf@suse.de>
2015-04-21 15:21:28 +02:00
..
boot powerpc: dts: pq3/85xx: Fix GPIO address 2015-01-29 23:04:32 -06:00
configs The clock framework changes for 3.20 contain the usual driver additions, 2015-02-21 12:30:30 -08:00
crypto crypto: add missing crypto module aliases 2015-01-13 22:29:11 +11:00
include kvmppc: Implement H_LOGICAL_CI_{LOAD,STORE} in KVM 2015-04-21 15:21:28 +02:00
kernel powerpc/book3s: Fix the MCE code to use CONFIG_KVM_BOOK3S_64_HANDLER 2015-03-23 17:10:47 +11:00
kvm kvmppc: Implement H_LOGICAL_CI_{LOAD,STORE} in KVM 2015-04-21 15:21:28 +02:00
lib powerpc: Export __spin_yield 2015-04-21 15:21:28 +02:00
math-emu powerpc: Correct emulated mtfsf instruction 2014-04-07 10:33:11 +10:00
mm powerpc: drop _PAGE_FILE and pte_file()-related helpers 2015-02-16 17:56:05 -08:00
net module: remove mod arg from module_free, rename module_memfree(). 2015-01-20 11:38:33 +10:30
oprofile powerpc updates for 3.19 2014-12-11 17:48:14 -08:00
perf Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into next 2015-02-04 12:03:21 +11:00
platforms Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 10:27:28 -07:00
sysdev powerpc: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:36 -08:00
xmon powerpc updates for 3.20 2015-02-11 18:15:38 -08:00
Kconfig powerpc/mm: fix undefined reference to `.__kernel_map_pages' on FSL PPC64 2015-01-28 14:22:22 +11:00
Kconfig.debug Patch queue for ppc - 2014-08-01 2014-08-05 09:58:11 +02:00
Makefile kbuild: do not add $(call ...) to invoke cc-version or cc-fullversion 2015-01-09 17:25:44 +01:00
relocs_check.pl Fix warning typo "CONFIG_RELCOATABLE" 2013-05-29 15:11:30 +02:00