On Thu, Apr 11, 2019 at 10:00:03AM +0200, Cédric Le Goater wrote: > From: Benjamin Herrenschmidt <b...@kernel.crashing.org> > > On some architectures, PTE updates for dirty and changed bits need > to be performed atomically. This adds a couple of address_space_cmpxchg* > helpers for that purpose. > > Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> > Signed-off-by: Cédric Le Goater <c...@kaod.org>
Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
But I think this needs to go past Paolo for review as memory subsystem
maintainer.
> ---
> include/exec/memory_ldst.inc.h | 6 +++
> memory_ldst.inc.c | 80 ++++++++++++++++++++++++++++++++++
> 2 files changed, 86 insertions(+)
>
> diff --git a/include/exec/memory_ldst.inc.h b/include/exec/memory_ldst.inc.h
> index 272c20f02eae..f3cfa7e9a622 100644
> --- a/include/exec/memory_ldst.inc.h
> +++ b/include/exec/memory_ldst.inc.h
> @@ -28,6 +28,12 @@ extern uint64_t glue(address_space_ldq, SUFFIX)(ARG1_DECL,
> hwaddr addr, MemTxAttrs attrs, MemTxResult *result);
> extern void glue(address_space_stl_notdirty, SUFFIX)(ARG1_DECL,
> hwaddr addr, uint32_t val, MemTxAttrs attrs, MemTxResult *result);
> +extern uint32_t glue(address_space_cmpxchgl_notdirty, SUFFIX)(ARG1_DECL,
> + hwaddr addr, uint32_t old, uint32_t new, MemTxAttrs attrs,
> + MemTxResult *result);
> +extern uint32_t glue(address_space_cmpxchgq_notdirty, SUFFIX)(ARG1_DECL,
> + hwaddr addr, uint64_t old, uint64_t new, MemTxAttrs attrs,
> + MemTxResult *result);
> extern void glue(address_space_stw, SUFFIX)(ARG1_DECL,
> hwaddr addr, uint32_t val, MemTxAttrs attrs, MemTxResult *result);
> extern void glue(address_space_stl, SUFFIX)(ARG1_DECL,
> diff --git a/memory_ldst.inc.c b/memory_ldst.inc.c
> index acf865b900d7..1d58d2fea67d 100644
> --- a/memory_ldst.inc.c
> +++ b/memory_ldst.inc.c
> @@ -320,6 +320,86 @@ void glue(address_space_stl_notdirty, SUFFIX)(ARG1_DECL,
> RCU_READ_UNLOCK();
> }
>
> +/* This is meant to be used for atomic PTE updates under MT-TCG */
> +uint32_t glue(address_space_cmpxchgl_notdirty, SUFFIX)(ARG1_DECL,
> + hwaddr addr, uint32_t old, uint32_t new, MemTxAttrs attrs,
> + MemTxResult *result)
> +{
> + uint8_t *ptr;
> + MemoryRegion *mr;
> + hwaddr l = 4;
> + hwaddr addr1;
> + MemTxResult r;
> + uint8_t dirty_log_mask;
> +
> + /* Must test result */
> + assert(result);
> +
> + RCU_READ_LOCK();
> + mr = TRANSLATE(addr, &addr1, &l, true, attrs);
> + if (l < 4 || !memory_access_is_direct(mr, true)) {
> + r = MEMTX_ERROR;
> + } else {
> + uint32_t orig = old;
> +
> + ptr = qemu_map_ram_ptr(mr->ram_block, addr1);
> + old = atomic_cmpxchg(ptr, orig, new);
> +
> + if (old == orig) {
> + dirty_log_mask = memory_region_get_dirty_log_mask(mr);
> + dirty_log_mask &= ~(1 << DIRTY_MEMORY_CODE);
> +
> cpu_physical_memory_set_dirty_range(memory_region_get_ram_addr(mr) +
> + addr, 4, dirty_log_mask);
> + }
> + r = MEMTX_OK;
> + }
> + *result = r;
> + RCU_READ_UNLOCK();
> +
> + return old;
> +}
> +
> +#ifdef CONFIG_ATOMIC64
> +/* This is meant to be used for atomic PTE updates under MT-TCG */
> +uint32_t glue(address_space_cmpxchgq_notdirty, SUFFIX)(ARG1_DECL,
> + hwaddr addr, uint64_t old, uint64_t new, MemTxAttrs attrs,
> + MemTxResult *result)
> +{
> + uint8_t *ptr;
> + MemoryRegion *mr;
> + hwaddr l = 8;
> + hwaddr addr1;
> + MemTxResult r;
> + uint8_t dirty_log_mask;
> +
> + /* Must test result */
> + assert(result);
> +
> + RCU_READ_LOCK();
> + mr = TRANSLATE(addr, &addr1, &l, true, attrs);
> + if (l < 8 || !memory_access_is_direct(mr, true)) {
> + r = MEMTX_ERROR;
> + } else {
> + uint32_t orig = old;
> +
> + ptr = qemu_map_ram_ptr(mr->ram_block, addr1);
> + old = atomic_cmpxchg(ptr, orig, new);
> +
> + if (old == orig) {
> + dirty_log_mask = memory_region_get_dirty_log_mask(mr);
> + dirty_log_mask &= ~(1 << DIRTY_MEMORY_CODE);
> +
> cpu_physical_memory_set_dirty_range(memory_region_get_ram_addr(mr) +
> + addr, 8, dirty_log_mask);
> + }
> + r = MEMTX_OK;
> + }
> + *result = r;
> + RCU_READ_UNLOCK();
> +
> + return old;
> +}
> +#endif /* CONFIG_ATOMIC64 */
> +
> /* warning: addr must be aligned */
> static inline void glue(address_space_stl_internal, SUFFIX)(ARG1_DECL,
> hwaddr addr, uint32_t val, MemTxAttrs attrs,
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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