| Message ID | 1478165243-4767-6-git-send-email-jasowang@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 03/11/2016 10:27, Jason Wang wrote: > This patch introduces a helper to query the iotlb entry for a > possible iova. This will be used by later device IOTLB API to enable > the capability for a dataplane (e.g vhost) to query the IOTLB. > > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com> > Cc: Richard Henderson <rth@twiddle.net> > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > exec.c | 33 +++++++++++++++++++++++++++++++++ > include/exec/memory.h | 6 ++++++ > 2 files changed, 39 insertions(+) > > diff --git a/exec.c b/exec.c > index b1094c0..00c7a2b 100644 > --- a/exec.c > +++ b/exec.c > @@ -449,6 +449,39 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x > } > > /* Called from RCU critical section */ > +IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr, > + bool is_write) > +{ > + IOMMUTLBEntry iotlb = {0}; > + MemoryRegionSection *section; > + MemoryRegion *mr; > + hwaddr plen; plen must be initialized on entry to address_space_translate_internal, since it's set to MIN(plen, MIN(section->size, addr - section->offset_within_address_space)) after address_space_translate_internal calls address_space_lookup_region. But you don't really need plen, so you should do this: section = address_space_lookup_region(d, addr, false); addr = addr - section->offset_within_address_space + section->offset_within_region; instead of section = address_space_translate_internal(d, addr, &addr, &plen, true); and then you don't even need a plen anymore. Also: > + for (;;) { > + AddressSpaceDispatch *d = atomic_rcu_read(&as->dispatch); > + section = address_space_translate_internal(d, addr, &addr, &plen, true); > + mr = section->mr; > + > + if (!mr->iommu_ops) { > + break; > + } > + > + iotlb = mr->iommu_ops->translate(mr, addr, is_write); > + addr = ((iotlb.translated_addr & ~iotlb.addr_mask) > + | (addr & iotlb.addr_mask)); This addr assignment is only needed after the iotlb.perm check, so move it there. Thanks, Paolo > + plen = MIN(plen, (addr | iotlb.addr_mask) - addr + 1); > + if (!(iotlb.perm & (1 << is_write))) { > + iotlb.target_as = NULL; > + break; > + } > + > + as = iotlb.target_as; > + } > + > + return iotlb; > +} > + > +/* Called from RCU critical section */ > MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr, > hwaddr *xlat, hwaddr *plen, > bool is_write) > diff --git a/include/exec/memory.h b/include/exec/memory.h > index 9728a2f..e605de3 100644 > --- a/include/exec/memory.h > +++ b/include/exec/memory.h > @@ -1404,6 +1404,12 @@ void address_space_stq_le(AddressSpace *as, hwaddr addr, uint64_t val, > void address_space_stq_be(AddressSpace *as, hwaddr addr, uint64_t val, > MemTxAttrs attrs, MemTxResult *result); > > +/* address_space_get_iotlb_entry: translate an address into an IOTLB > + * entry. Should be called from an RCU critical section. > + */ > +IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr, > + bool is_write); > + > /* address_space_translate: translate an address range into an address space > * into a MemoryRegion and an address range into that section. Should be > * called from an RCU critical section, to avoid that the last reference >
On 2016年11月04日 01:03, Paolo Bonzini wrote: > > On 03/11/2016 10:27, Jason Wang wrote: >> This patch introduces a helper to query the iotlb entry for a >> possible iova. This will be used by later device IOTLB API to enable >> the capability for a dataplane (e.g vhost) to query the IOTLB. >> >> Cc: Paolo Bonzini <pbonzini@redhat.com> >> Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com> >> Cc: Richard Henderson <rth@twiddle.net> >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> --- >> exec.c | 33 +++++++++++++++++++++++++++++++++ >> include/exec/memory.h | 6 ++++++ >> 2 files changed, 39 insertions(+) >> >> diff --git a/exec.c b/exec.c >> index b1094c0..00c7a2b 100644 >> --- a/exec.c >> +++ b/exec.c >> @@ -449,6 +449,39 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x >> } >> >> /* Called from RCU critical section */ >> +IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr, >> + bool is_write) >> +{ >> + IOMMUTLBEntry iotlb = {0}; >> + MemoryRegionSection *section; >> + MemoryRegion *mr; >> + hwaddr plen; > plen must be initialized on entry to address_space_translate_internal, > since it's set to > > MIN(plen, MIN(section->size, > addr - section->offset_within_address_space)) > > after address_space_translate_internal calls > address_space_lookup_region. But you don't really need plen, so you > should do this: > > section = address_space_lookup_region(d, addr, false); > addr = addr > - section->offset_within_address_space > + section->offset_within_region; > > instead of > > section = address_space_translate_internal(d, addr, &addr, > &plen, true); > > and then you don't even need a plen anymore. Cool, will do this in next version. > > Also: > > >> + for (;;) { >> + AddressSpaceDispatch *d = atomic_rcu_read(&as->dispatch); >> + section = address_space_translate_internal(d, addr, &addr, &plen, true); >> + mr = section->mr; >> + >> + if (!mr->iommu_ops) { >> + break; >> + } >> + >> + iotlb = mr->iommu_ops->translate(mr, addr, is_write); >> + addr = ((iotlb.translated_addr & ~iotlb.addr_mask) >> + | (addr & iotlb.addr_mask)); > This addr assignment is only needed after the iotlb.perm check, so move > it there. > > Thanks, > > Paolo Right. Thanks > >> + plen = MIN(plen, (addr | iotlb.addr_mask) - addr + 1); >> + if (!(iotlb.perm & (1 << is_write))) { >> + iotlb.target_as = NULL; >> + break; >> + } >> + >> + as = iotlb.target_as; >> + } >> + >> + return iotlb; >> +} >> + >> +/* Called from RCU critical section */ >> MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr, >> hwaddr *xlat, hwaddr *plen, >> bool is_write) >> diff --git a/include/exec/memory.h b/include/exec/memory.h >> index 9728a2f..e605de3 100644 >> --- a/include/exec/memory.h >> +++ b/include/exec/memory.h >> @@ -1404,6 +1404,12 @@ void address_space_stq_le(AddressSpace *as, hwaddr addr, uint64_t val, >> void address_space_stq_be(AddressSpace *as, hwaddr addr, uint64_t val, >> MemTxAttrs attrs, MemTxResult *result); >> >> +/* address_space_get_iotlb_entry: translate an address into an IOTLB >> + * entry. Should be called from an RCU critical section. >> + */ >> +IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr, >> + bool is_write); >> + >> /* address_space_translate: translate an address range into an address space >> * into a MemoryRegion and an address range into that section. Should be >> * called from an RCU critical section, to avoid that the last reference >>
diff --git a/exec.c b/exec.c index b1094c0..00c7a2b 100644 --- a/exec.c +++ b/exec.c @@ -449,6 +449,39 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x } /* Called from RCU critical section */ +IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr, + bool is_write) +{ + IOMMUTLBEntry iotlb = {0}; + MemoryRegionSection *section; + MemoryRegion *mr; + hwaddr plen; + + for (;;) { + AddressSpaceDispatch *d = atomic_rcu_read(&as->dispatch); + section = address_space_translate_internal(d, addr, &addr, &plen, true); + mr = section->mr; + + if (!mr->iommu_ops) { + break; + } + + iotlb = mr->iommu_ops->translate(mr, addr, is_write); + addr = ((iotlb.translated_addr & ~iotlb.addr_mask) + | (addr & iotlb.addr_mask)); + plen = MIN(plen, (addr | iotlb.addr_mask) - addr + 1); + if (!(iotlb.perm & (1 << is_write))) { + iotlb.target_as = NULL; + break; + } + + as = iotlb.target_as; + } + + return iotlb; +} + +/* Called from RCU critical section */ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr, hwaddr *xlat, hwaddr *plen, bool is_write) diff --git a/include/exec/memory.h b/include/exec/memory.h index 9728a2f..e605de3 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -1404,6 +1404,12 @@ void address_space_stq_le(AddressSpace *as, hwaddr addr, uint64_t val, void address_space_stq_be(AddressSpace *as, hwaddr addr, uint64_t val, MemTxAttrs attrs, MemTxResult *result); +/* address_space_get_iotlb_entry: translate an address into an IOTLB + * entry. Should be called from an RCU critical section. + */ +IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr, + bool is_write); + /* address_space_translate: translate an address range into an address space * into a MemoryRegion and an address range into that section. Should be * called from an RCU critical section, to avoid that the last reference
This patch introduces a helper to query the iotlb entry for a possible iova. This will be used by later device IOTLB API to enable the capability for a dataplane (e.g vhost) to query the IOTLB. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Signed-off-by: Jason Wang <jasowang@redhat.com> --- exec.c | 33 +++++++++++++++++++++++++++++++++ include/exec/memory.h | 6 ++++++ 2 files changed, 39 insertions(+)