From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/2] arm: KVM: keep arm vfp/simd exit handling consistent with arm64
Date: Thu, 18 Jun 2015 18:27:18 +0100 [thread overview]
Message-ID: <5582FF76.6060100@arm.com> (raw)
In-Reply-To: <1434491452-19177-3-git-send-email-m.smarduch@samsung.com>
On 16/06/15 22:50, Mario Smarduch wrote:
> After enhancing arm64 FP/SIMD exit handling, FP/SIMD exit branch is moved
> to guest trap handling. This keeps exiting handling flow between both
> architectures consistent.
>
> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
> ---
> arch/arm/kvm/interrupts.S | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
> index 79caf79..fca2c56 100644
> --- a/arch/arm/kvm/interrupts.S
> +++ b/arch/arm/kvm/interrupts.S
> @@ -363,10 +363,6 @@ hyp_hvc:
> @ Check syndrome register
> mrc p15, 4, r1, c5, c2, 0 @ HSR
> lsr r0, r1, #HSR_EC_SHIFT
> -#ifdef CONFIG_VFPv3
> - cmp r0, #HSR_EC_CP_0_13
> - beq switch_to_guest_vfp
> -#endif
> cmp r0, #HSR_EC_HVC
> bne guest_trap @ Not HVC instr.
>
> @@ -406,6 +402,12 @@ THUMB( orr lr, #1)
> 1: eret
>
> guest_trap:
> +#ifdef CONFIG_VFPv3
> + /* Guest accessed VFP/SIMD registers, save host, restore Guest */
> + cmp r0, #HSR_EC_CP_0_13
> + beq switch_to_guest_fpsimd
> +#endif
> +
> load_vcpu @ Load VCPU pointer to r0
> str r1, [vcpu, #VCPU_HSR]
>
> @@ -478,7 +480,7 @@ guest_trap:
> * inject an undefined exception to the guest.
> */
> #ifdef CONFIG_VFPv3
> -switch_to_guest_vfp:
> +switch_to_guest_fpsimd:
Ah, I think I managed to confuse you in my previous comment.
On ARMv7, we call the floating point stuff VFP.
On ARMv8, we call it FP/SIMD.
Not very consistent, I know...
> load_vcpu @ Load VCPU pointer to r0
It would be interesting to find out if we can make this load_vcpu part
of the common sequence (without spilling another register, of course).
Probably involves moving the exception class to r2.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <marc.zyngier@arm.com>
To: Mario Smarduch <m.smarduch@samsung.com>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"christoffer.dall@linaro.org" <christoffer.dall@linaro.org>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <Will.Deacon@arm.com>
Subject: Re: [PATCH v2 2/2] arm: KVM: keep arm vfp/simd exit handling consistent with arm64
Date: Thu, 18 Jun 2015 18:27:18 +0100 [thread overview]
Message-ID: <5582FF76.6060100@arm.com> (raw)
In-Reply-To: <1434491452-19177-3-git-send-email-m.smarduch@samsung.com>
On 16/06/15 22:50, Mario Smarduch wrote:
> After enhancing arm64 FP/SIMD exit handling, FP/SIMD exit branch is moved
> to guest trap handling. This keeps exiting handling flow between both
> architectures consistent.
>
> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
> ---
> arch/arm/kvm/interrupts.S | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
> index 79caf79..fca2c56 100644
> --- a/arch/arm/kvm/interrupts.S
> +++ b/arch/arm/kvm/interrupts.S
> @@ -363,10 +363,6 @@ hyp_hvc:
> @ Check syndrome register
> mrc p15, 4, r1, c5, c2, 0 @ HSR
> lsr r0, r1, #HSR_EC_SHIFT
> -#ifdef CONFIG_VFPv3
> - cmp r0, #HSR_EC_CP_0_13
> - beq switch_to_guest_vfp
> -#endif
> cmp r0, #HSR_EC_HVC
> bne guest_trap @ Not HVC instr.
>
> @@ -406,6 +402,12 @@ THUMB( orr lr, #1)
> 1: eret
>
> guest_trap:
> +#ifdef CONFIG_VFPv3
> + /* Guest accessed VFP/SIMD registers, save host, restore Guest */
> + cmp r0, #HSR_EC_CP_0_13
> + beq switch_to_guest_fpsimd
> +#endif
> +
> load_vcpu @ Load VCPU pointer to r0
> str r1, [vcpu, #VCPU_HSR]
>
> @@ -478,7 +480,7 @@ guest_trap:
> * inject an undefined exception to the guest.
> */
> #ifdef CONFIG_VFPv3
> -switch_to_guest_vfp:
> +switch_to_guest_fpsimd:
Ah, I think I managed to confuse you in my previous comment.
On ARMv7, we call the floating point stuff VFP.
On ARMv8, we call it FP/SIMD.
Not very consistent, I know...
> load_vcpu @ Load VCPU pointer to r0
It would be interesting to find out if we can make this load_vcpu part
of the common sequence (without spilling another register, of course).
Probably involves moving the exception class to r2.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2015-06-18 17:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-16 21:50 [PATCH v2 0/2] arm/arm64: KVM: Optimize arm64 fp/simd, saves 30-50% on exits Mario Smarduch
2015-06-16 21:50 ` Mario Smarduch
2015-06-16 21:50 ` [PATCH v2 1/2] arm64: KVM: Optimize arm64 fp/simd save/restore Mario Smarduch
2015-06-16 21:50 ` Mario Smarduch
2015-06-18 17:04 ` Marc Zyngier
2015-06-18 17:04 ` Marc Zyngier
2015-06-16 21:50 ` [PATCH v2 2/2] arm: KVM: keep arm vfp/simd exit handling consistent with arm64 Mario Smarduch
2015-06-16 21:50 ` Mario Smarduch
2015-06-18 17:27 ` Marc Zyngier [this message]
2015-06-18 17:27 ` Marc Zyngier
2015-06-18 23:49 ` Mario Smarduch
2015-06-18 23:49 ` Mario Smarduch
2015-06-19 13:50 ` Marc Zyngier
2015-06-19 13:50 ` Marc Zyngier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5582FF76.6060100@arm.com \
--to=marc.zyngier@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.