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Date: Thu, 6 Aug 2020 10:26:24 +0800 From: yangerkun <yangerkun@...wei.com> To: <linux-kernel@...r.kernel.org>, <gregkh@...uxfoundation.org>, <james.morse@....com>, <maz@...nel.org>, <drjones@...hat.com>, <marc.zyngier@....com>, <christoffer.dall@...aro.org> CC: <stable-commits@...r.kernel.org>, <kvm@...r.kernel.org> Subject: Re: Patch "KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts" has been added to the 4.4-stable tree Hi, Not familiar with kvm. And I have a question about this patch. Maybe backport this patch 3204be4109ad("KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts") without 52f6c4f02164 ("KVM: arm64: Change 32-bit handling of VM system registers") seems not right? Thanks, Kun. 在 2020/6/16 18:56, gregkh@...uxfoundation.org 写道: > > This is a note to let you know that I've just added the patch titled > > KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts > > to the 4.4-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > kvm-arm64-make-vcpu_cp1x-work-on-big-endian-hosts.patch > and it can be found in the queue-4.4 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@...r.kernel.org> know about it. > > >>>From 3204be4109ad681523e3461ce64454c79278450a Mon Sep 17 00:00:00 2001 > From: Marc Zyngier <maz@...nel.org> > Date: Tue, 9 Jun 2020 08:40:35 +0100 > Subject: KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts > > From: Marc Zyngier <maz@...nel.org> > > commit 3204be4109ad681523e3461ce64454c79278450a upstream. > > AArch32 CP1x registers are overlayed on their AArch64 counterparts > in the vcpu struct. This leads to an interesting problem as they > are stored in their CPU-local format, and thus a CP1x register > doesn't "hit" the lower 32bit portion of the AArch64 register on > a BE host. > > To workaround this unfortunate situation, introduce a bias trick > in the vcpu_cp1x() accessors which picks the correct half of the > 64bit register. > > Cc: stable@...r.kernel.org > Reported-by: James Morse <james.morse@....com> > Tested-by: James Morse <james.morse@....com> > Acked-by: James Morse <james.morse@....com> > Signed-off-by: Marc Zyngier <maz@...nel.org> > Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> > > --- > arch/arm64/include/asm/kvm_host.h | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -178,8 +178,10 @@ struct kvm_vcpu_arch { > * CP14 and CP15 live in the same array, as they are backed by the > * same system registers. > */ > -#define vcpu_cp14(v,r) ((v)->arch.ctxt.copro[(r)]) > -#define vcpu_cp15(v,r) ((v)->arch.ctxt.copro[(r)]) > +#define CPx_BIAS IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) > + > +#define vcpu_cp14(v,r) ((v)->arch.ctxt.copro[(r) ^ CPx_BIAS]) > +#define vcpu_cp15(v,r) ((v)->arch.ctxt.copro[(r) ^ CPx_BIAS]) > > #ifdef CONFIG_CPU_BIG_ENDIAN > #define vcpu_cp15_64_high(v,r) vcpu_cp15((v),(r)) > > > Patches currently in stable-queue which might be from maz@...nel.org are > > queue-4.4/kvm-arm64-make-vcpu_cp1x-work-on-big-endian-hosts.patch > > . >
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