From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.smarduch@samsung.com (Mario Smarduch) Date: Thu, 18 Dec 2014 14:25:21 -0800 Subject: Help on kvm_tlb_flush_vmid_ipa usage In-Reply-To: <54932D1F.5060209@arm.com> References: <54932A97.3060103@samsung.com> <54932D1F.5060209@arm.com> Message-ID: <54935451.6090405@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 12/18/2014 11:38 AM, Marc Zyngier wrote: > On 18/12/14 19:27, Mario Smarduch wrote: >> When this function is called IPA address is used. Looking at the HYP >> implementation it uses the IPA directly in tlbi instructions. But >> reading the TLB maintnance instruction syntax, bit [35:0] should be >> set to IPA[47:12]. I traced the source code but don't see the >> adjustment. I must be missing something given this function is >> fundamental to KVM MMU. > > Ermmm... Someone (that is, I) needs a brown paper back again. > > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > index b72aa9f..a767f6a 100644 > --- a/arch/arm64/kvm/hyp.S > +++ b/arch/arm64/kvm/hyp.S > @@ -1014,6 +1014,7 @@ ENTRY(__kvm_tlb_flush_vmid_ipa) > * Instead, we invalidate Stage-2 for this IPA, and the > * whole of Stage-1. Weep... > */ > + lsr x1, x1, #12 > tlbi ipas2e1is, x1 > /* > * We have to ensure completion of the invalidation at Stage-2, > > M. > Hi Marc, fwiw I re-ran the test that halts the host (on foundation model) with a guest booted, panic has gone away. BUG: Bad page state in process K20nfsserver pfn:ff818 page:ffff7c7fc37e4540 count:-3 mapcount:0 mapping: (null) index:0x0 flags: 0x0() page dumped because: nonzero _count Modules linked in: CPU: 1 PID: 761 Comm: K20nfsserver Not tainted 3.18.0-rc2+ #55 Call trace: [] dump_backtrace+0x0/0x12c [] show_stack+0x10/0x1c [] dump_stack+0x74/0x98 [] bad_page+0xdc/0x12c [] get_page_from_freelist+0x4b4/0x600 [] __alloc_pages_nodemask+0xdc/0x780 [] __get_free_pages+0x14/0x5c [] get_zeroed_page+0x10/0x1c [] pgd_alloc+0xc/0x18 [] mm_init+0xcc/0x12c [] mm_alloc+0x44/0x54 [] do_execve+0x1a8/0x49c [] SyS_execve+0x1c/0x2c