Depending on the client activity, the server can be asked to open a huge
number of file descriptors and eventually hit RLIMIT_NOFILE. This is
currently mitigated using a reclaim logic : the server closes the file
descriptors of idle fids, based on the assumption that it will be able
to re-open them later. This assumption doesn't hold of course if the
client requests the file to be unlinked. In this case, we loop on the
entire fid list and mark all related fids as unreclaimable (the reclaim
logic will just ignore them) and, of course, we open or re-open their
file descriptors if needed since we're about to unlink the file.
This is the purpose of v9fs_mark_fids_unreclaim(). Since the actual
opening of a file can cause the coroutine to yield, another client
request could possibly add a new fid that we may want to mark as
non-reclaimable as well. The loop is thus restarted if the re-open
request was actually transmitted to the backend. This is achieved
by keeping a reference on the first fid (head) before traversing
the list.
This is wrong in several ways:
- a potential clunk request from the client could tear the first
fid down and cause the reference to be stale. This leads to a
use-after-free error that can be detected with ASAN, using a
custom 9p client
- fids are added at the head of the list : restarting from the
previous head will always miss fids added by a some other
potential request
All these problems could be avoided if fids were being added at the
end of the list. This can be achieved with a QSIMPLEQ, but this is
probably too much change for a bug fix. For now let's keep it
simple and just restart the loop from the current head.
Fixes: CVE-2021-20181
Buglink: https://bugs.launchpad.net/qemu/+bug/1911666
Reported-by: Zero Day Initiative <zdi-disclosures@trendmicro.com>
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Message-Id: <161064025265.1838153.15185571283519390907.stgit@bahia.lan>
Signed-off-by: Greg Kurz <groug@kaod.org>
nanoMIPS not a CPU, but an ISA. The nanoMIPS ISA is already
defined as ISA_NANOMIPS32.
Remove this incorrect definition and update the single CPU
implementing it, the I7200.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210112210152.2072996-3-f4bug@amsat.org>
LL/SC opcodes have been removed from the Release 6.
Add a single decodetree entry for the opcodes, triggering
Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() calls.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-14-f4bug@amsat.org>
LLD/SCD opcodes have been removed from the Release 6.
Add a single decodetree entry for the opcodes, triggering
Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() calls.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-13-f4bug@amsat.org>
LDL/LDR/SDL/SDR opcodes have been removed from the Release 6.
Add a single decodetree entry for the opcodes, triggering
Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() calls.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-12-f4bug@amsat.org>
LWLE/LWRE/SWLE/SWRE (EVA) opcodes have been removed from
the Release 6. Add a single decodetree entry for the opcodes,
triggering Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() calls.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-11-f4bug@amsat.org>
LWL/LWR/SWL/SWR opcodes have been removed from the Release 6.
Add a single decodetree entry for the opcodes, triggering
Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() calls.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-10-f4bug@amsat.org>
CACHE/PREF opcodes have been removed from the Release 6.
Add a single decodetree entry for the opcodes, triggering
Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() calls.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-9-f4bug@amsat.org>
COP1x opcode has been removed from the Release 6.
Add a single decodetree entry for it, triggering
Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() call.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-8-f4bug@amsat.org>
Special2 opcode have been removed from the Release 6.
Add a single decodetree entry for all the opcode class,
triggering Reserved Instruction if ever used.
Remove unreachable check_insn_opc_removed() call.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201208203704.243704-7-f4bug@amsat.org>
LSA and LDSA opcodes are also available with MIPS release 6.
Introduce the decodetree config files and call the decode()
helpers in the main decode_opc() loop.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201215225757.764263-24-f4bug@amsat.org>
Extract 2200 lines from the huge translate.c to a new file,
'msa_translate.c'. As there are too many inter-dependencies
we don't compile it as another object yet, but keep including
it in the big translate.o. We gain in code maintainability.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201120210844.2625602-5-f4bug@amsat.org>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
The msa_wr_d[] registers are only initialized/used by MSA.
They are declared static. We want to move them to the new
'msa_translate.c' unit in few commits, without having to
declare them global (with extern).
Extract first the logic initialization of the MSA registers
from the generic initialization. We will later move this
function along with the MSA registers to the new C unit.
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <20201208003702.4088927-8-f4bug@amsat.org>
Commits 863f264d10 ("add msa_reset(), global msa register") and
cb269f273f ("fix multiple TCG registers covering same data")
removed the FPU scalar registers and replaced them by aliases to
the MSA vector registers.
It is not very clear to have FPU registers displayed with MSA
register names, even if MSA ASE is not present.
Instead of aliasing FPU registers to the MSA ones (even when MSA
is absent), we now alias the MSA ones to the FPU ones (only when
MSA is present).
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <20201208003702.4088927-7-f4bug@amsat.org>
Only decode MSA opcodes if MSA is present (implemented).
Now than check_msa_access() will only be called if MSA is
present, the only way to have MIPS_HFLAG_MSA unset is if
MSA is disabled (bit CP0C5_MSAEn cleared, see previous
commit). Therefore we can remove the 'reserved instruction'
exception.
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <20201208003702.4088927-5-f4bug@amsat.org>
To allow compiling 64-bit specific translation code more
generically (and removing #ifdef'ry), allow compiling
check_mips_64() on 32-bit targets.
If ever called on 32-bit, we obviously emit a reserved
instruction exception.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <20201215225757.764263-3-f4bug@amsat.org>
As we will slowly move to decodetree generated decoders,
extract the legacy decoding from decode_opc(), so new
decoders are added in decode_opc() while old code is
removed from decode_opc_legacy().
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201215225757.764263-2-f4bug@amsat.org>
Some CPU translation functions / registers / macros and
definitions can be used by ISA / ASE / extensions out of
the big translate.c file. Declare them in "translate.h".
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201207235539.4070364-3-f4bug@amsat.org>
