| Message ID | 20180305083655.6186-5-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/7] openpic_kvm: drop address_space_to_flatview call | expand |
On 05/03/18 19:36, Paolo Bonzini wrote: > address_space_read is calling address_space_to_flatview but it can > be called outside the RCU lock. To fix it, push the rcu_read_lock/unlock > pair up from flatview_read_full to address_space_read's constant size > fast path and address_space_read_full. > > Cc: qemu-stable@nongnu.org > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> > --- > exec.c | 44 ++++++++++++++++++++++++++++---------------- > include/exec/memory.h | 25 ++++++++++--------------- > 2 files changed, 38 insertions(+), 31 deletions(-) > > diff --git a/exec.c b/exec.c > index 0b74b58d45..55b7452bd7 100644 > --- a/exec.c > +++ b/exec.c > @@ -2612,6 +2612,8 @@ static const MemoryRegionOps watch_mem_ops = { > }, > }; > > +static MemTxResult flatview_read(FlatView *fv, hwaddr addr, > + MemTxAttrs attrs, uint8_t *buf, int len); > static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs, > const uint8_t *buf, int len); > static bool flatview_access_valid(FlatView *fv, hwaddr addr, int len, > @@ -3161,24 +3163,18 @@ MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr, > return result; > } > > -MemTxResult flatview_read_full(FlatView *fv, hwaddr addr, > - MemTxAttrs attrs, uint8_t *buf, int len) > +/* Called from RCU critical section. */ > +static MemTxResult flatview_read(FlatView *fv, hwaddr addr, > + MemTxAttrs attrs, uint8_t *buf, int len) > { > hwaddr l; > hwaddr addr1; > MemoryRegion *mr; > - MemTxResult result = MEMTX_OK; > - > - if (len > 0) { > - rcu_read_lock(); > - l = len; > - mr = flatview_translate(fv, addr, &addr1, &l, false); > - result = flatview_read_continue(fv, addr, attrs, buf, len, > - addr1, l, mr); > - rcu_read_unlock(); > - } > > - return result; > + l = len; > + mr = flatview_translate(fv, addr, &addr1, &l, false); > + return flatview_read_continue(fv, addr, attrs, buf, len, > + addr1, l, mr); > } > > static MemTxResult flatview_rw(FlatView *fv, hwaddr addr, MemTxAttrs attrs, > @@ -3199,6 +3195,22 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, > addr, attrs, buf, len, is_write); > } > > +MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr, > + MemTxAttrs attrs, uint8_t *buf, int len) > +{ > + MemTxResult result = MEMTX_OK; > + FlatView *fv; > + > + if (len > 0) { > + rcu_read_lock(); > + fv = address_space_to_flatview(as); > + result = flatview_read(fv, addr, attrs, buf, len); > + rcu_read_unlock(); > + } > + > + return result; > +} > + > MemTxResult address_space_write(AddressSpace *as, hwaddr addr, > MemTxAttrs attrs, > const uint8_t *buf, int len) > diff --git a/include/exec/memory.h b/include/exec/memory.h > index 6c8e394675..54ff81fbd1 100644 > --- a/include/exec/memory.h > +++ b/include/exec/memory.h > @@ -1894,13 +1894,12 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len, > > > /* Internal functions, part of the implementation of address_space_read. */ > +MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr, > + MemTxAttrs attrs, uint8_t *buf, int len); > MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr, > MemTxAttrs attrs, uint8_t *buf, > int len, hwaddr addr1, hwaddr l, > MemoryRegion *mr); > - > -MemTxResult flatview_read_full(FlatView *fv, hwaddr addr, > - MemTxAttrs attrs, uint8_t *buf, int len); > void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr); > > static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write) > @@ -1919,25 +1918,28 @@ static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write) > * > * Return a MemTxResult indicating whether the operation succeeded > * or failed (eg unassigned memory, device rejected the transaction, > - * IOMMU fault). > + * IOMMU fault). Called within RCU critical section. > * > - * @fv: #FlatView to be accessed > + * @as: #AddressSpace to be accessed > * @addr: address within that address space > * @attrs: memory transaction attributes > * @buf: buffer with the data transferred > */ > static inline __attribute__((__always_inline__)) > -MemTxResult flatview_read(FlatView *fv, hwaddr addr, MemTxAttrs attrs, > - uint8_t *buf, int len) > +MemTxResult address_space_read(AddressSpace *as, hwaddr addr, > + MemTxAttrs attrs, uint8_t *buf, > + int len) > { > MemTxResult result = MEMTX_OK; > hwaddr l, addr1; > void *ptr; > MemoryRegion *mr; > + FlatView *fv; > > if (__builtin_constant_p(len)) { > if (len) { > rcu_read_lock(); > + fv = address_space_to_flatview(as); > l = len; > mr = flatview_translate(fv, addr, &addr1, &l, false); > if (len == l && memory_access_is_direct(mr, false)) { > @@ -1950,18 +1952,11 @@ MemTxResult flatview_read(FlatView *fv, hwaddr addr, MemTxAttrs attrs, > rcu_read_unlock(); > } > } else { > - result = flatview_read_full(fv, addr, attrs, buf, len); > + result = address_space_read_full(as, addr, attrs, buf, len); > } > return result; > } > > -static inline MemTxResult address_space_read(AddressSpace *as, hwaddr addr, > - MemTxAttrs attrs, uint8_t *buf, > - int len) > -{ > - return flatview_read(address_space_to_flatview(as), addr, attrs, buf, len); > -} > - > /** > * address_space_read_cached: read from a cached RAM region > * >
diff --git a/exec.c b/exec.c index 0b74b58d45..55b7452bd7 100644 --- a/exec.c +++ b/exec.c @@ -2612,6 +2612,8 @@ static const MemoryRegionOps watch_mem_ops = { }, }; +static MemTxResult flatview_read(FlatView *fv, hwaddr addr, + MemTxAttrs attrs, uint8_t *buf, int len); static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs, const uint8_t *buf, int len); static bool flatview_access_valid(FlatView *fv, hwaddr addr, int len, @@ -3161,24 +3163,18 @@ MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr, return result; } -MemTxResult flatview_read_full(FlatView *fv, hwaddr addr, - MemTxAttrs attrs, uint8_t *buf, int len) +/* Called from RCU critical section. */ +static MemTxResult flatview_read(FlatView *fv, hwaddr addr, + MemTxAttrs attrs, uint8_t *buf, int len) { hwaddr l; hwaddr addr1; MemoryRegion *mr; - MemTxResult result = MEMTX_OK; - - if (len > 0) { - rcu_read_lock(); - l = len; - mr = flatview_translate(fv, addr, &addr1, &l, false); - result = flatview_read_continue(fv, addr, attrs, buf, len, - addr1, l, mr); - rcu_read_unlock(); - } - return result; + l = len; + mr = flatview_translate(fv, addr, &addr1, &l, false); + return flatview_read_continue(fv, addr, attrs, buf, len, + addr1, l, mr); } static MemTxResult flatview_rw(FlatView *fv, hwaddr addr, MemTxAttrs attrs, @@ -3199,6 +3195,22 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, addr, attrs, buf, len, is_write); } +MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr, + MemTxAttrs attrs, uint8_t *buf, int len) +{ + MemTxResult result = MEMTX_OK; + FlatView *fv; + + if (len > 0) { + rcu_read_lock(); + fv = address_space_to_flatview(as); + result = flatview_read(fv, addr, attrs, buf, len); + rcu_read_unlock(); + } + + return result; +} + MemTxResult address_space_write(AddressSpace *as, hwaddr addr, MemTxAttrs attrs, const uint8_t *buf, int len) diff --git a/include/exec/memory.h b/include/exec/memory.h index 6c8e394675..54ff81fbd1 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -1894,13 +1894,12 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len, /* Internal functions, part of the implementation of address_space_read. */ +MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr, + MemTxAttrs attrs, uint8_t *buf, int len); MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr, MemTxAttrs attrs, uint8_t *buf, int len, hwaddr addr1, hwaddr l, MemoryRegion *mr); - -MemTxResult flatview_read_full(FlatView *fv, hwaddr addr, - MemTxAttrs attrs, uint8_t *buf, int len); void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr); static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write) @@ -1919,25 +1918,28 @@ static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write) * * Return a MemTxResult indicating whether the operation succeeded * or failed (eg unassigned memory, device rejected the transaction, - * IOMMU fault). + * IOMMU fault). Called within RCU critical section. * - * @fv: #FlatView to be accessed + * @as: #AddressSpace to be accessed * @addr: address within that address space * @attrs: memory transaction attributes * @buf: buffer with the data transferred */ static inline __attribute__((__always_inline__)) -MemTxResult flatview_read(FlatView *fv, hwaddr addr, MemTxAttrs attrs, - uint8_t *buf, int len) +MemTxResult address_space_read(AddressSpace *as, hwaddr addr, + MemTxAttrs attrs, uint8_t *buf, + int len) { MemTxResult result = MEMTX_OK; hwaddr l, addr1; void *ptr; MemoryRegion *mr; + FlatView *fv; if (__builtin_constant_p(len)) { if (len) { rcu_read_lock(); + fv = address_space_to_flatview(as); l = len; mr = flatview_translate(fv, addr, &addr1, &l, false); if (len == l && memory_access_is_direct(mr, false)) { @@ -1950,18 +1952,11 @@ MemTxResult flatview_read(FlatView *fv, hwaddr addr, MemTxAttrs attrs, rcu_read_unlock(); } } else { - result = flatview_read_full(fv, addr, attrs, buf, len); + result = address_space_read_full(as, addr, attrs, buf, len); } return result; } -static inline MemTxResult address_space_read(AddressSpace *as, hwaddr addr, - MemTxAttrs attrs, uint8_t *buf, - int len) -{ - return flatview_read(address_space_to_flatview(as), addr, attrs, buf, len); -} - /** * address_space_read_cached: read from a cached RAM region *
address_space_read is calling address_space_to_flatview but it can be called outside the RCU lock. To fix it, push the rcu_read_lock/unlock pair up from flatview_read_full to address_space_read's constant size fast path and address_space_read_full. Cc: qemu-stable@nongnu.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- exec.c | 44 ++++++++++++++++++++++++++++---------------- include/exec/memory.h | 25 ++++++++++--------------- 2 files changed, 38 insertions(+), 31 deletions(-)