From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59289) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zjnlp-0004cn-0d for qemu-devel@nongnu.org; Wed, 07 Oct 2015 08:24:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zjnll-0000Ql-TS for qemu-devel@nongnu.org; Wed, 07 Oct 2015 08:24:33 -0400 Received: from mail-wi0-f179.google.com ([209.85.212.179]:38637) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zjnll-0000Qb-Nk for qemu-devel@nongnu.org; Wed, 07 Oct 2015 08:24:29 -0400 Received: by wiclk2 with SMTP id lk2so25740557wic.1 for ; Wed, 07 Oct 2015 05:24:29 -0700 (PDT) References: <1443911939-2825-1-git-send-email-edgar.iglesias@gmail.com> <1443911939-2825-3-git-send-email-edgar.iglesias@gmail.com> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <1443911939-2825-3-git-send-email-edgar.iglesias@gmail.com> Date: Wed, 07 Oct 2015 13:24:27 +0100 Message-ID: <87a8ruyih0.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v3 2/9] target-arm: Add computation of starting level for S2 PTW List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Edgar E. Iglesias" Cc: edgar.iglesias@xilinx.com, peter.maydell@linaro.org, qemu-devel@nongnu.org, agraf@suse.de, laurent.desnogues@gmail.com, serge.fdrv@gmail.com Edgar E. Iglesias writes: > From: "Edgar E. Iglesias" > > The starting level for S2 pagetable walks is computed > differently from the S1 starting level. Implement the S2 > variant. > > Signed-off-by: Edgar E. Iglesias > --- > target-arm/helper.c | 39 +++++++++++++++++++++++++++------------ > 1 file changed, 27 insertions(+), 12 deletions(-) > > diff --git a/target-arm/helper.c b/target-arm/helper.c > index 5a5e5f0..507324f 100644 > --- a/target-arm/helper.c > +++ b/target-arm/helper.c > @@ -6549,18 +6549,33 @@ static bool get_phys_addr_lpae(CPUARMState *env, target_ulong address, > goto do_fault; > } > > - /* The starting level depends on the virtual address size (which can be > - * up to 48 bits) and the translation granule size. It indicates the number > - * of strides (granule_sz bits at a time) needed to consume the bits > - * of the input address. In the pseudocode this is: > - * level = 4 - RoundUp((inputsize - grainsize) / stride) > - * where their 'inputsize' is our 'va_size - tsz', 'grainsize' is > - * our 'granule_sz + 3' and 'stride' is our 'granule_sz'. > - * Applying the usual "rounded up m/n is (m+n-1)/n" and simplifying: > - * = 4 - (va_size - tsz - granule_sz - 3 + granule_sz - 1) / granule_sz > - * = 4 - (va_size - tsz - 4) / granule_sz; > - */ > - level = 4 - (va_size - tsz - 4) / granule_sz; > + if (mmu_idx != ARMMMUIdx_S2NS) { > + /* The starting level depends on the virtual address size (which can > + * be up to 48 bits) and the translation granule size. It indicates > + * the number of strides (granule_sz bits at a time) needed to > + * consume the bits of the input address. In the pseudocode this is: > + * level = 4 - RoundUp((inputsize - grainsize) / stride) > + * where their 'inputsize' is our 'va_size - tsz', 'grainsize' is > + * our 'granule_sz + 3' and 'stride' is our 'granule_sz'. > + * Applying the usual "rounded up m/n is (m+n-1)/n" and simplifying: > + * = 4 - (va_size - tsz - granule_sz - 3 + granule_sz - 1) / granule_sz > + * = 4 - (va_size - tsz - 4) / granule_sz; > + */ > + level = 4 - (va_size - tsz - 4) / granule_sz; > + } else { > + unsigned int startlevel = extract32(tcr->raw_tcr, 6, 2); Maybe an assert(startlevel<3) would be useful? > + > + /* For stage 2 translations the starting level is specified by the > + * VCTR_EL2.SL0 field (whose interpretation depends on the page size) > + */ > + if (granule_sz == 9) { > + /* 4K pages */ > + level = 2 - startlevel; > + } else { > + /* 16K or 64K pages */ > + level = 3 - startlevel; > + } > + } > > /* Clear the vaddr bits which aren't part of the within-region address, > * so that we don't have to special case things when calculating the Reviewed-by: Alex Bennée -- Alex Bennée