fa48b43 "target-ppc: Remove hack for ppc_hash64_load_hpte*() with HV KVM"
purports to remove a hack in the handling of hash page tables (HPTs)
managed by KVM instead of qemu. However, it actually went in the wrong
direction.
That patch requires anything looking for an external HPT (that is one not
managed by the guest itself) to check both env->external_htab (for a qemu
managed HPT) and kvmppc_kern_htab (for a KVM managed HPT). That's a
problem because kvmppc_kern_htab is local to mmu-hash64.c, but some places
which need to check for an external HPT are outside that, such as
kvm_arch_get_registers(). The latter was subtly broken by the earlier
patch such that gdbstub can no longer access memory.
Basically a KVM managed HPT is much more like a qemu managed HPT than it is
like a guest managed HPT, so the original "hack" was actually on the right
track.
This partially reverts fa48b43, so we again mark a KVM managed external HPT
by putting a special but non-NULL value in env->external_htab. It then
goes further, using that marker to eliminate the kvmppc_kern_htab global
entirely. The ppc_hash64_set_external_hpt() helper function is extended
to set that marker if passed a NULL value (if you're setting an external
HPT, but don't have an actual HPT to set, the assumption is that it must
be a KVM managed HPT).
This also has some flow-on changes to the HPT access helpers, required by
the above changes.
Reported-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Tested-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
When a Power cpu with 64-bit hash MMU has it's hash page table (HPT)
pointer updated by a write to the SDR1 register we need to update some
derived variables. Likewise, when the cpu is configured for an external
HPT (one not in the guest memory space) some derived variables need to be
updated.
Currently the logic for this is (partially) duplicated in ppc_store_sdr1()
and in spapr_cpu_reset(). In future we're going to need it in some other
places, so make some common helpers for this update.
In addition the new ppc_hash64_set_external_hpt() helper also updates
SDR1 in KVM - it's not updated by the normal runtime KVM <-> qemu CPU
synchronization. In a sense this belongs logically in the
ppc_hash64_set_sdr1() helper, but that is called from
kvm_arch_get_registers() so can't itself call cpu_synchronize_state()
without infinite recursion. In practice this doesn't matter because
the only other caller is TCG specific.
Currently there aren't situations where updating SDR1 at runtime in KVM
matters, but there are going to be in future.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
With HV KVM, the guest's hash page table (HPT) is managed by the kernel and
not directly accessible to QEMU. This means that spapr->htab is NULL
and normally env->external_htab would also be NULL for each cpu.
However, that would cause ppc_hash64_load_hpte*() to do the wrong thing in
the few cases where QEMU does need to load entries from the in-kernel HPT.
Specifically, seeing external_htab is NULL, they would look for an HPT
within the guest's address space instead.
To stop that we have an ugly hack in the pseries machine type code to
set external htab to (void *)1 instead.
This patch removes that hack by having ppc_hash64_load_hpte*() explicitly
check kvmppc_kern_htab instead, which makes more sense.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Now that the TCG and spapr code has been extended to allow (semi-)
arbitrary page encodings in the CPU's 'sps' table, we can add the many
page sizes supported by real POWER7 and POWER8 hardware that we previously
didn't support in TCG.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
h_enter() in the spapr code needs to know the page size of the HPTE it's
about to insert. Unlike other paths that do this, it doesn't have access
to the SLB, so at the moment it determines this with some open-coded
tests which assume POWER7 or POWER8 page size encodings.
To make this more flexible add ppc_hash64_hpte_page_shift_noslb() to
determine both the "base" page size per segment, and the individual
effective page size from an HPTE alone.
This means that the spapr code should now be able to handle any page size
listed in the env->sps table.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
When HPTEs are removed or modified by hypercalls on spapr, we need to
invalidate the relevant pages in the qemu TLB.
Currently we do that by doing some complicated calculations to work out the
right encoding for the tlbie instruction, then passing that to
ppc_tlb_invalidate_one()... which totally ignores the argument and flushes
the whole tlb.
Avoid that by adding a new flush-by-hpte helper in mmu-hash64.c.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
ppc_store_slb updates the SLB for PPC cpus with 64-bit hash MMUs.
Currently it takes two parameters, which contain values encoded as the
register arguments to the slbmte instruction, one register contains the
ESID portion of the SLBE and also the slot number, the other contains the
VSID portion of the SLBE.
We're shortly going to want to do some SLB updates from other code where
it is more convenient to supply the slot number and ESID separately, so
rework this function and its callers to work this way.
As a bonus, this slightly simplifies the emulation of segment registers for
when running a 32-bit OS on a 64-bit CPU.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
Like a lot of places these files include a mixture of functions taking
both the older CPUPPCState *env and newer PowerPCCPU *cpu. Move a step
closer to cleaning this up by standardizing on PowerPCCPU, except for the
helper_* functions which are called with the CPUPPCState * from tcg.
Callers and some related functions are updated as well, the boundaries of
what's changed here are a bit arbitrary.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
We look at two sizes specified in ISA (4K, 64K). If not found matching,
we consider it 16MB.
Without this patch we would fail to lookup address above 16MB range.
Below 16MB happened to work before because the kernel have a liner
mapping and we always looked up hash for 0xc000000000000000. The
actual real address was computed by using the 16MB offset
with the real address found with the above hash.
Without Fix:
(gdb) x/16x 0xc000000001000000
0xc000000001000000 <list_entries+453208>: Cannot access memory at address 0xc000000001000000
(gdb)
With Fix:
(gdb) x/16x 0xc000000001000000
0xc000000001000000 <list_entries+453208>: 0x00000000 0x00000000 0x00000000 0x00000000
0xc000000001000010 <list_entries+453224>: 0x00000000 0x00000000 0x00000000 0x00000000
0xc000000001000020 <list_entries+453240>: 0x00000000 0x00000000 0x00000000 0x00000000
0xc000000001000030 <list_entries+453256>: 0x00000000 0x00000000 0x00000000 0x00000000
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
Commits fdfba1a298,
ab1da85791,
f606604f1c and
2c17449b30 added usages of ENV_GET_CPU()
macro in target-specific code.
Use ppc_env_get_cpu() instead.
Cc: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
This support updating htab managed by the hypervisor. Currently we don't have
any user for this feature. This actually bring the store_hpte interface
in-line with the load_hpte one. We may want to use this when we want to
emulate henter hcall in qemu for HV kvm.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[ folded fix for the "warn_unused_result" build break in
kvmppc_hash64_write_pte(), Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
For updating in kernel htab we need to provide both pte0 and pte1, hence update
the interface to take pte0 and pte1 together
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[ ldq_phys() API change, Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
With kvm enabled, we store the hash page table information in the hypervisor.
Use ioctl to read the htab contents. Without this we get the below error when
trying to read the guest address
(gdb) x/10 do_fork
0xc000000000098660 <do_fork>: Cannot access memory at address 0xc000000000098660
(gdb)
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[ fixes for 32 bit build (casts!), ldq_phys() API change,
Greg Kurz <gkurz@linux.vnet.ibm.com ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Version 2.06 of the Power architecture describes an additional page
protection mechanism. Each virtual page has a "class" (0-31) recorded in
the PTE. The AMR register contains bits which can prohibit reads and/or
writes on a class by class basis. Interestingly, the AMR is userspace
readable and writable, however user mode writes are masked by the contents
of the UAMOR which is privileged.
This patch implements this protection mechanism, along with the AMR and
UAMOR SPRs. The architecture also specifies a hypervisor-privileged AMOR
register which masks user and supervisor writes to the AMR and UAMOR. We
leave this out for now, since we don't at present model hypervisor mode
correctly in any case.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[agraf: fix 32-bit hosts]
Signed-off-by: Alexander Graf <agraf@suse.de>
find_pte{32,64{() do several things. First they search through a PTEG
ooking for a PTE matching our virtual address. Then they do permissions
checking and other processing on that PTE.
This patch separates the search by VA out from the rest. The search is
combined with the pte{32,64}_match() functions into new
ppc_has{32,64}_pteg_search() functions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
On real hardware the ppc hash page table is stored in memory; accordingly
our mmu emulation code can read a hash page table in guest memory. But,
when paravirtualized under PAPR, the real hash page table is in host
memory, accessible to the guest only via hypercalls. We model this by
also allowing the MMU emulation code to access a specially allocated hash
page table outside the guest's memory image. At present these two options
are implemented with some ugly conditionals at each access point in the mmu
emulation code. In the implementation of the PAPR hypercalls, we assume
the external hash table.
This patch cleans things up by adding helpers to load and store from the
hash table for both 32-bit and 64-bit hash mmus. The 64-bit versions
handle both the in-guest-memory and outside guest memory cases. The 32-bit
versions only handle the in-guest-memory case since no 32-bit systems can
have an external hash table at present.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently cpu.h contains a number of definitions relating to the 64-bit
hash MMU. Some are used in the MMU emulation code, but some are only used
in the spapr MMU management hcall implementations.
This patch moves these definitions (except for a few that are needed
more widely) into mmu-hash64.h header, shared between the MMU emulation
code and the spapr hcall code. The MMU emulation code is also updated to
actually use a number of those definitions in place of hard coded
constants.
Similarly, we add new analogous definitions to mmu-hash32.h and use those
in place of many hard-coded constants in mmu-hash32.c
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[agraf: fix 32-bit hosts]
Signed-off-by: Alexander Graf <agraf@suse.de>
cpu_get_phys_page_debug() is a trivial wrapper around
get_physical_address(). But even the signature of
get_physical_address() has some things we'd like to clean up on a
per-mmu basis, so this patch moves the test on mmu model out to
cpu_get_phys_page_debug(), moving the version for 64-bit hash MMUs out
to mmu-hash64.c and the version for 32-bit hash MMUs to mmu-hash32.c
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
cpu_ppc_handle_mmu_fault() calls get_physical_address() (whose behaviour
depends on MMU type) then, if that fails, issues an appropriate exception
- which again has a number of dependencies on MMU type.
This patch starts converting cpu_ppc_handle_mmu_fault() to have a
single switch on MMU type, calling MMU specific fault handler
functions which deal with both translation and exception delivery
appropriately for the MMU type. We convert 32-bit and 64-bit hash
MMUs to this new model, but the existing code is left in place for
other MMU types for now.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
Depending on the MSR state, for 64-bit hash MMUs, get_physical_address
can either call check_physical (which has further tests for mmu type)
or get_segment64. Similarly for 32-bit hash MMUs we can either call
check_physucal or get_bat() and get_segment32().
This patch splits off the whole get_physical_addresss() path for hash
MMUs into 32-bit and 64-bit versions, handling real mode correctly for
such MMUs without going to check_physical and rechecking the mmu type.
Correspondingly, the hash MMU specific paths in check_physical() are
removed.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
The poorly named get_segment() function handles most of the address
translation logic for hash-based MMUs. It has many ugly conditionals on
whether the MMU is 32-bit or 64-bit.
This patch splits the function into 32 and 64-bit versions, using the
switch on mmu_type that's already in the caller
(get_physical_address()) to select the right one. Most of the
original function remains in mmu_helper.c to support the 6xx software
loaded TLB implementations (cleaning those up is a project for another
day).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
32-bit and 64-bit hash MMU implementations currently share a find_pte
function. This results in a whole bunch of ugly conditionals in the shared
function, and not all that much actually shared code.
This patch separates out the 32-bit and 64-bit versions, putting then
in mmu-hash64.c and mmu-has32.c, and removes the conditionals from
both versions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently support for both 32-bit and 64-bit hash MMUs share an
implementation of pte_check. But there are enough differences that this
means the shared function has several very ugly conditionals on "is_64b".
This patch cleans things up by separating out the 64-bit version
(putting it into mmu-hash64.c) and the 32-bit hash version (putting it
in mmu-hash32.c). Another copy remains in mmu_helper.c, which is used
for the 6xx software loaded TLB paths.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
As a first step to disentangling the handling for 64-bit hash MMUs from
the rest, we move the code handling the Segment Lookaside Buffer (SLB)
(which only exists on 64-bit hash MMUs) into a new mmu-hash64.c file.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
