Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-24 Thread Richard Henderson
On 07/20/2015 10:19 PM, Benjamin Herrenschmidt wrote: > Currently, we get to the slow path for any unaligned access in the > backend, because we effectively preserve the bottom address bits > below the alignment requirement when comparing with the TLB entry, > so any non-0 bit there will cause the

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Benjamin Herrenschmidt
On Tue, 2015-07-21 at 16:18 +0200, Alexander Graf wrote: > I can happily take on this after my paternity leave, but considering > that I'm out for 3 months in 1 month from now and have a pretty huge > pile of stuff that needs to get done until then I'd rather keep > things > low right now ;) >

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Benjamin Herrenschmidt
On Tue, 2015-07-21 at 15:48 +0200, Paolo Bonzini wrote: > > On 21/07/2015 14:26, Benjamin Herrenschmidt wrote: > >> > So who can pick those up? PPC TCG is pretty much unmaintained since Malc > >> > disappeared, no? > > Did you just raise your hand ? :-) > > > > Worst case I'm happy to just keep

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Aurelien Jarno
On 2015-07-21 14:04, Alexander Graf wrote: > On 07/21/15 11:46, Benjamin Herrenschmidt wrote: > >On Tue, 2015-07-21 at 07:39 +0100, Richard Henderson wrote: > >>On 07/21/2015 07:33 AM, Benjamin Herrenschmidt wrote: > >>>On Tue, 2015-07-21 at 07:27 +0100, Richard Henderson wrote: > On 07/21/2015

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Aurelien Jarno
On 2015-07-21 15:19, Benjamin Herrenschmidt wrote: > Currently, we get to the slow path for any unaligned access in the > backend, because we effectively preserve the bottom address bits > below the alignment requirement when comparing with the TLB entry, > so any non-0 bit there will cause the com

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Alexander Graf
On 07/21/15 15:48, Paolo Bonzini wrote: On 21/07/2015 14:26, Benjamin Herrenschmidt wrote: So who can pick those up? PPC TCG is pretty much unmaintained since Malc disappeared, no? Did you just raise your hand ? :-) Worst case I'm happy to just keep a branch of my things that have had externa

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Paolo Bonzini
On 21/07/2015 14:26, Benjamin Herrenschmidt wrote: >> > So who can pick those up? PPC TCG is pretty much unmaintained since Malc >> > disappeared, no? > Did you just raise your hand ? :-) > > Worst case I'm happy to just keep a branch of my things that have had > external reviews and directly g

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Benjamin Herrenschmidt
On Tue, 2015-07-21 at 14:04 +0200, Alexander Graf wrote: > >> Reviewed-by: Richard Henderson > > Thanks. > > So who can pick those up? PPC TCG is pretty much unmaintained since Malc > disappeared, no? Did you just raise your hand ? :-) Worst case I'm happy to just keep a branch of my things t

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Alexander Graf
On 07/21/15 11:46, Benjamin Herrenschmidt wrote: On Tue, 2015-07-21 at 07:39 +0100, Richard Henderson wrote: On 07/21/2015 07:33 AM, Benjamin Herrenschmidt wrote: On Tue, 2015-07-21 at 07:27 +0100, Richard Henderson wrote: On 07/21/2015 06:19 AM, Benjamin Herrenschmidt wrote: +/* Clear th

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-21 Thread Benjamin Herrenschmidt
On Tue, 2015-07-21 at 07:39 +0100, Richard Henderson wrote: > On 07/21/2015 07:33 AM, Benjamin Herrenschmidt wrote: > > On Tue, 2015-07-21 at 07:27 +0100, Richard Henderson wrote: > >> On 07/21/2015 06:19 AM, Benjamin Herrenschmidt wrote: > >>> +/* Clear the non-page, non-alignment bits from th

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-20 Thread Richard Henderson
On 07/21/2015 07:33 AM, Benjamin Herrenschmidt wrote: On Tue, 2015-07-21 at 07:27 +0100, Richard Henderson wrote: On 07/21/2015 06:19 AM, Benjamin Herrenschmidt wrote: +/* Clear the non-page, non-alignment bits from the address */ if (TCG_TARGET_REG_BITS == 32 || TARGET_LONG_BITS ==

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-20 Thread Benjamin Herrenschmidt
On Tue, 2015-07-21 at 07:27 +0100, Richard Henderson wrote: > On 07/21/2015 06:19 AM, Benjamin Herrenschmidt wrote: > > +/* Clear the non-page, non-alignment bits from the address */ > > if (TCG_TARGET_REG_BITS == 32 || TARGET_LONG_BITS == 32) { > > +/* We don't support unaligned

Re: [Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-20 Thread Richard Henderson
On 07/21/2015 06:19 AM, Benjamin Herrenschmidt wrote: +/* Clear the non-page, non-alignment bits from the address */ if (TCG_TARGET_REG_BITS == 32 || TARGET_LONG_BITS == 32) { +/* We don't support unaligned accesses on 32-bits, preserve + * the bottom bits and thus trigg

[Qemu-devel] [PATCH v3] tcg/ppc: Improve unaligned load/store handling on 64-bit backend

2015-07-20 Thread Benjamin Herrenschmidt
Currently, we get to the slow path for any unaligned access in the backend, because we effectively preserve the bottom address bits below the alignment requirement when comparing with the TLB entry, so any non-0 bit there will cause the compare to fail. For the same number of instructions, we can