This commit attempts to fix a technical hiccup first mentioned by Richard
Henderson in
https://lists.nongnu.org/archive/html/qemu-devel/2021-05/msg06247.html
To sumarize the hiccup here, when radix-style mmus are translating an
address, they might need to call a second level of translation, with
hypervisor privileges. However, the way it was being done up until
this point meant that the second level translation had the same
privileges as the first level. It could lead to a bug in address
translation when running KVM inside a TCG guest, but this bug was never
experienced by users, so this isn't as much a bug fix as it is a
correctness cleanup.
This patch attempts that cleanup by making radix64_*_xlate functions
receive the mmu_idx, and passing one with the correct permission for the
second level translation.
The mmuidx macros added by this patch are only correct for non-bookE
mmus, because BookE style set the IS and DS bits inverted and there
might be other subtle differences. However, there doesn't seem to be
BookE cpus that have radix-style mmus, so we left a comment there to
document the issue, in case a machine does have that and was missed.
As part of this cleanup, we now need to send the correct mmmu_idx
when calling get_phys_page_debug, otherwise we might not be able to see the
memory that the CPU could
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Bruno Larsen (billionai) <bruno.larsen@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20210628133610.1143-2-bruno.larsen@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Create one common dispatch for all of the ppc_*_xlate functions.
Use ppc64_v3_radix to directly dispatch between ppc_radix64_xlate
and ppc_hash64_xlate.
Remove the separate *_handle_mmu_fault and *_get_phys_page_debug
functions, using common code for ppc_cpu_tlb_fill and
ppc_cpu_get_phys_page_debug.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210621125115.67717-9-bruno.larsen@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
These changes were waiting until we didn't need to match
the function type of PowerPCCPUClass.handle_mmu_fault.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210621125115.67717-3-bruno.larsen@eldorado.org.br>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This doesn't require write access to the CPU structure.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <158941060817.240484.14621015211317485106.stgit@bahia.lan>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
That "b" means "base address" and thus shouldn't be in the name
of actual entries and related constants.
This patch keeps the synthetic patb_entry field of the spapr
virtual hypervisor unchanged until I figure out if that has
an impact on the migration stream.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190215170029.15641-11-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
In target/ppc/mmu-hash64.c there already exists the function
ppc_hash64_get_phys_page_debug() to get the physical (real) address for
a given effective address in hash mode.
Implement the function ppc_radix64_get_phys_page_debug() to allow a real
address to be obtained for a given effective address in radix mode.
This is used when a debugger is attached to qemu.
Previously we just had a comment saying this is unimplemented which then
fell through to the default case and caused an abort due to
unrecognised mmu model as the default had no case for the V3 mmu, which
was misleading at best.
We reuse ppc_radix64_walk_tree() which is used by the radix fault
handler since the process of walking the radix tree is identical.
Reported-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
ISA V3.00 introduced a new radix mmu model. Implement the page fault
handler for this so we can run a tcg guest in radix mode and perform
address translation correctly.
In real mode (mmu turned off) addresses are masked to remove the top
4 bits and then are subject to partition scoped translation, since we only
support pseries at this stage it is only necessary to perform the masking
and then we're done.
In virtual mode (mmu turned on) address translation if performed as
follows:
1. Use the quadrant to determine the fully qualified address.
The fully qualified address is defined as the combination of the effective
address, the effective logical partition id (LPID) and the effective
process id (PID). Based on the quadrant (EA63:62) we set the pid and lpid
like so:
quadrant 0: lpid = LPIDR, pid = PIDR
quadrant 1: HV only (not allowed in pseries)
quadrant 2: HV only (not allowed in pseries)
quadrant 3: lpid = LPIDR, pid = 0
If we can't get the fully qualified address we raise a segment interrupt.
2. Find the guest radix tree
We ask the virtual hypervisor for the partition table which was registered
with H_REGISTER_PROC_TBL which points us to the process table in guest
memory. We then index this table by pid to get the process table entry
which points us to the appropriate radix tree to translate the address.
If the process table isn't big enough to contain an entry for the current
pid then we raise a storage interrupt.
3. Walk the radix tree
Next we walk the radix tree where each level is a table of page directory
entries indexed by some number of bits from the effective address, where
the number of bits is determined by the table size. We continue to walk
the tree (while entries are valid and the table is of minimum size) until
we reach a table of page table entries, indicated by having the leaf bit
set. The appropriate pte is then checked for sufficient access permissions,
the reference and change bits are updated and the real address is
calculated from the real page number bits of the pte and the low bits of
the effective address.
If we can't find an entry or can't access the entry bacause of permissions
then we raise a storage interrupt.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
[dwg: Add missing parentheses to macro]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
