linux-kernel - Re: [PATCH V2] KVM: arm64: Implement vq

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Date:   Mon, 10 Jun 2019 15:20:30 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Dave Martin <Dave.Martin@....com>
Cc:     Marc Zyngier <marc.zyngier@....com>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry@....com>,
        Suzuki K Pouloze <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        kvmarm@...ts.cs.columbia.edu, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2] KVM: arm64: Implement vq_present() as a macro

On 10-06-19, 10:09, Dave Martin wrote:
> You could drop the extra level of indirection on vqs now.  The only
> thing it achieves is to enforce the size of the array via type-
> checkout, but the macro can't easily do that (unless you can think
> of another way to do it).
> 
> Otherwise, looks good.

Below is what I wrote initially this morning and then moved to the
current version as I wasn't sure if you would want that :)

-- 
viresh

-------------------------8<-------------------------

>From be823e68faffc82a6f621c16ce1bd45990d92791 Mon Sep 17 00:00:00 2001
Message-Id: <be823e68faffc82a6f621c16ce1bd45990d92791.1560160165.git.viresh.kumar@...aro.org>
From: Viresh Kumar <viresh.kumar@...aro.org>
Date: Mon, 10 Jun 2019 11:15:17 +0530
Subject: [PATCH] KVM: arm64: Implement vq_present() as a macro

This routine is a one-liner and doesn't really need to be function and
can be implemented as a macro.

Suggested-by: Dave Martin <Dave.Martin@....com>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 arch/arm64/kvm/guest.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 3ae2f82fca46..ae734fcfd4ea 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -207,13 +207,7 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 
 #define vq_word(vq) (((vq) - SVE_VQ_MIN) / 64)
 #define vq_mask(vq) ((u64)1 << ((vq) - SVE_VQ_MIN) % 64)
-
-static bool vq_present(
-	const u64 (*const vqs)[KVM_ARM64_SVE_VLS_WORDS],
-	unsigned int vq)
-{
-	return (*vqs)[vq_word(vq)] & vq_mask(vq);
-}
+#define vq_present(vqs, vq) ((vqs)[vq_word(vq)] & vq_mask(vq))
 
 static int get_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 {
@@ -258,7 +252,7 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 
 	max_vq = 0;
 	for (vq = SVE_VQ_MIN; vq <= SVE_VQ_MAX; ++vq)
-		if (vq_present(&vqs, vq))
+		if (vq_present(vqs, vq))
 			max_vq = vq;
 
 	if (max_vq > sve_vq_from_vl(kvm_sve_max_vl))
@@ -272,7 +266,7 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	 * maximum:
 	 */
 	for (vq = SVE_VQ_MIN; vq <= max_vq; ++vq)
-		if (vq_present(&vqs, vq) != sve_vq_available(vq))
+		if (vq_present(vqs, vq) != sve_vq_available(vq))
 			return -EINVAL;
 
 	/* Can't run with no vector lengths at all: */
-- 
2.21.0.rc0.269.g1a574e7a288b