The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().
The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.
The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)
There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Most of the registers used by the FEAT_MOPS instructions cannot use
31 as a register field value; this is CONSTRAINED UNPREDICTABLE to
NOP or UNDEF (we UNDEF). However, it is permitted for the "source
value" register for the memset insns SET* to be 31, which (as usual
for most data-processing insns) means it should be the zero register
XZR. We forgot to handle this case, with the effect that trying to
set memory to zero with a "SET* Xd, Xn, XZR" sets the memory to
the value that happens to be in the low byte of SP.
Handle XZR when getting the SET* data value from the register file.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20231030174000.3792225-4-peter.maydell@linaro.org
Implement the SET* instructions which collectively implement a
"memset" operation. These come in a set of three, eg SETP
(prologue), SETM (main), SETE (epilogue), and each of those has
different flavours to indicate whether memory accesses should be
unpriv or non-temporal.
This commit does not include the "memset with tag setting"
SETG* instructions.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230912140434.1333369-8-peter.maydell@linaro.org
The architecture requires (R_TYTWB) that an attempt to return from EL3
when SCR_EL3.{NSE,NS} are {1,0} is an illegal exception return. (This
enforces that the CPU can't ever be executing below EL3 with the
NSE,NS bits indicating an invalid security state.)
We were missing this check; add it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230807150618.101357-1-peter.maydell@linaro.org
