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Message-ID: <CA+CK2bDc+9EsH_TLTgg9Pqv_-rZfZfPohdZEfsYjT8ss+8skjg@mail.gmail.com>
Date: Thu, 8 Apr 2021 10:45:18 -0400
From: Pavel Tatashin <pasha.tatashin@...een.com>
To: Marc Zyngier <maz@...nel.org>
Cc: James Morris <jmorris@...ei.org>, Sasha Levin <sashal@...nel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
kexec mailing list <kexec@...ts.infradead.org>,
LKML <linux-kernel@...r.kernel.org>,
Jonathan Corbet <corbet@....net>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
James Morse <james.morse@....com>,
Vladimir Murzin <vladimir.murzin@....com>,
Matthias Brugger <matthias.bgg@...il.com>,
linux-mm <linux-mm@...ck.org>,
Mark Rutland <mark.rutland@....com>, steve.capper@....com,
rfontana@...hat.com, Thomas Gleixner <tglx@...utronix.de>,
Selin Dag <selindag@...il.com>,
Tyler Hicks <tyhicks@...ux.microsoft.com>,
Pingfan Liu <kernelfans@...il.com>
Subject: Re: [PATCH v13 03/18] arm64: hyp-stub: Move el1_sync into the vectors
On Thu, Apr 8, 2021 at 6:24 AM Marc Zyngier <maz@...nel.org> wrote:
>
> On 2021-04-08 05:05, Pavel Tatashin wrote:
> > From: James Morse <james.morse@....com>
> >
> > The hyp-stub's el1_sync code doesn't do very much, this can easily fit
> > in the vectors.
> >
> > With this, all of the hyp-stubs behaviour is contained in its vectors.
> > This lets kexec and hibernate copy the hyp-stub when they need its
> > behaviour, instead of re-implementing it.
> >
> > Signed-off-by: James Morse <james.morse@....com>
> >
> > [Fixed merging issues]
>
> That's a pretty odd fix IMO.
>
> >
> > Signed-off-by: Pavel Tatashin <pasha.tatashin@...een.com>
> > ---
> > arch/arm64/kernel/hyp-stub.S | 59 ++++++++++++++++++------------------
> > 1 file changed, 29 insertions(+), 30 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/hyp-stub.S
> > b/arch/arm64/kernel/hyp-stub.S
> > index ff329c5c074d..d1a73d0f74e0 100644
> > --- a/arch/arm64/kernel/hyp-stub.S
> > +++ b/arch/arm64/kernel/hyp-stub.S
> > @@ -21,6 +21,34 @@ SYM_CODE_START_LOCAL(\label)
> > .align 7
> > b \label
> > SYM_CODE_END(\label)
> > +.endm
> > +
> > +.macro hyp_stub_el1_sync
> > +SYM_CODE_START_LOCAL(hyp_stub_el1_sync)
> > + .align 7
> > + cmp x0, #HVC_SET_VECTORS
> > + b.ne 2f
> > + msr vbar_el2, x1
> > + b 9f
> > +
> > +2: cmp x0, #HVC_SOFT_RESTART
> > + b.ne 3f
> > + mov x0, x2
> > + mov x2, x4
> > + mov x4, x1
> > + mov x1, x3
> > + br x4 // no return
> > +
> > +3: cmp x0, #HVC_RESET_VECTORS
> > + beq 9f // Nothing to reset!
> > +
> > + /* Someone called kvm_call_hyp() against the hyp-stub... */
> > + mov_q x0, HVC_STUB_ERR
> > + eret
> > +
> > +9: mov x0, xzr
> > + eret
> > +SYM_CODE_END(hyp_stub_el1_sync)
>
> You said you tested this on a TX2. I guess you don't care whether
> it runs VHE or not...
Hi Marc,
Thank you for noticing this. Not sure how this missmerge happened. I
have added the missing case, and VHE is initialized correctly during
boot.
[ 14.698175] kvm [1]: VHE mode initialized successfully
During normal boot, kexec reboot, and kdump reboot. I will respin the
series and send the version 14 soon.
Thanks,
Pasha
>
> M.
>
> > .endm
> >
> > .text
> > @@ -39,7 +67,7 @@ SYM_CODE_START(__hyp_stub_vectors)
> > invalid_vector hyp_stub_el2h_fiq_invalid // FIQ EL2h
> > invalid_vector hyp_stub_el2h_error_invalid // Error EL2h
> >
> > - ventry el1_sync // Synchronous 64-bit EL1
> > + hyp_stub_el1_sync // Synchronous 64-bit EL1
> > invalid_vector hyp_stub_el1_irq_invalid // IRQ 64-bit EL1
> > invalid_vector hyp_stub_el1_fiq_invalid // FIQ 64-bit EL1
> > invalid_vector hyp_stub_el1_error_invalid // Error 64-bit EL1
> > @@ -55,35 +83,6 @@ SYM_CODE_END(__hyp_stub_vectors)
> > # Check the __hyp_stub_vectors didn't overflow
> > .org . - (__hyp_stub_vectors_end - __hyp_stub_vectors) + SZ_2K
> >
> > -
> > -SYM_CODE_START_LOCAL(el1_sync)
> > - cmp x0, #HVC_SET_VECTORS
> > - b.ne 1f
> > - msr vbar_el2, x1
> > - b 9f
> > -
> > -1: cmp x0, #HVC_VHE_RESTART
> > - b.eq mutate_to_vhe
> > -
> > -2: cmp x0, #HVC_SOFT_RESTART
> > - b.ne 3f
> > - mov x0, x2
> > - mov x2, x4
> > - mov x4, x1
> > - mov x1, x3
> > - br x4 // no return
> > -
> > -3: cmp x0, #HVC_RESET_VECTORS
> > - beq 9f // Nothing to reset!
> > -
> > - /* Someone called kvm_call_hyp() against the hyp-stub... */
> > - mov_q x0, HVC_STUB_ERR
> > - eret
> > -
> > -9: mov x0, xzr
> > - eret
> > -SYM_CODE_END(el1_sync)
> > -
> > // nVHE? No way! Give me the real thing!
> > SYM_CODE_START_LOCAL(mutate_to_vhe)
> > // Sanity check: MMU *must* be off
>
> --
> Jazz is not dead. It just smells funny...
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