Re: [Xen-devel] [PATCH] KVM: arm64: add workaround for Cortex-A57 erratum #852523

2015-09-15 Thread Christoffer Dall
On Mon, Sep 14, 2015 at 04:46:28PM +0100, Marc Zyngier wrote: > On 14/09/15 16:06, Will Deacon wrote: > > When restoring the system register state for an AArch32 guest at EL2, > > writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57, > > which can lead to the guest effectively

Re: [Xen-devel] [PATCH] KVM: arm64: add workaround for Cortex-A57 erratum #852523

2015-09-15 Thread Ian Campbell
On Tue, 2015-09-15 at 00:08 +0100, Julien Grall wrote: > On 14/09/2015 16:58, Will Deacon wrote: > > > The Xen ctxt switch code[0] has DACR_EL2 in the midst of it all, and > > > certainly followed by some sysregs, which I've got my fingers crossed > > > happens to be sufficient (other than maybe

Re: [Xen-devel] [PATCH] KVM: arm64: add workaround for Cortex-A57 erratum #852523

2015-09-14 Thread Will Deacon
Hi Ian, On Mon, Sep 14, 2015 at 04:36:28PM +0100, Ian Campbell wrote: > On Mon, 2015-09-14 at 16:06 +0100, Will Deacon wrote: > > When restoring the system register state for an AArch32 guest at EL2, > > writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57, > > which can lead to

[Xen-devel] [PATCH] KVM: arm64: add workaround for Cortex-A57 erratum #852523

2015-09-14 Thread Will Deacon
When restoring the system register state for an AArch32 guest at EL2, writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57, which can lead to the guest effectively running with junk in the DACR and running into unexpected domain faults. This patch works around the issue by

Re: [Xen-devel] [PATCH] KVM: arm64: add workaround for Cortex-A57 erratum #852523

2015-09-14 Thread Marc Zyngier
On 14/09/15 16:06, Will Deacon wrote: > When restoring the system register state for an AArch32 guest at EL2, > writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57, > which can lead to the guest effectively running with junk in the DACR > and running into unexpected domain faults.

Re: [Xen-devel] [PATCH] KVM: arm64: add workaround for Cortex-A57 erratum #852523

2015-09-14 Thread Ian Campbell
On Mon, 2015-09-14 at 16:06 +0100, Will Deacon wrote: > When restoring the system register state for an AArch32 guest at EL2, > writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57, > which can lead to the guest effectively running with junk in the DACR > and running into

Re: [Xen-devel] [PATCH] KVM: arm64: add workaround for Cortex-A57 erratum #852523

2015-09-14 Thread Will Deacon
On Mon, Sep 14, 2015 at 04:46:28PM +0100, Marc Zyngier wrote: > On 14/09/15 16:06, Will Deacon wrote: > > When restoring the system register state for an AArch32 guest at EL2, > > writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57, > > which can lead to the guest effectively