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From: Dave Martin <Dave.Martin@arm.com>
To: kvmarm@lists.cs.columbia.edu
Cc: Okamoto Takayuki <tokamoto@jp.fujitsu.com>,
	Christoffer Dall <cdall@kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Zhang Lei <zhang.lei@jp.fujitsu.com>,
	Julien Grall <julien.grall@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 12/14] KVM: Clarify capability requirements for KVM_ARM_VCPU_FINALIZE
Date: Fri, 12 Apr 2019 17:28:16 +0100	[thread overview]
Message-ID: <1555086498-26691-13-git-send-email-Dave.Martin@arm.com> (raw)
In-Reply-To: <1555086498-26691-1-git-send-email-Dave.Martin@arm.com>

Userspace is only supposed to use KVM_ARM_VCPU_FINALIZE when there
is some vcpu feature that can actually be finalized.

This means that documenting KVM_ARM_VCPU_FINALIZE as available or
not depending on the capabilities present is not helpful.

This patch amends the documentation to describe availability in
terms of which capability is required for each finalizable feature
instead.

In any case, userspace sees the same error (EINVAL) regardless of
whether the given feature is not present or KVM_ARM_VCPU_FINALIZE
is not implemented at all.

No functional change.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
 Documentation/virtual/kvm/api.txt | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 68509de..b115b23 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3997,17 +3997,16 @@ userspace should not expect to get any particular value there.
 
 4.119 KVM_ARM_VCPU_FINALIZE
 
-Capability: KVM_CAP_ARM_SVE
 Architectures: arm, arm64
 Type: vcpu ioctl
 Parameters: int feature (in)
 Returns: 0 on success, -1 on error
 Errors:
   EPERM:     feature not enabled, needs configuration, or already finalized
-  EINVAL:    unknown feature
+  EINVAL:    feature unknown or not present
 
 Recognised values for feature:
-  arm64      KVM_ARM_VCPU_SVE
+  arm64      KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE)
 
 Finalizes the configuration of the specified vcpu feature.
 
-- 
2.1.4

WARNING: multiple messages have this Message-ID (diff)
From: Dave Martin <Dave.Martin@arm.com>
To: kvmarm@lists.cs.columbia.edu
Cc: Okamoto Takayuki <tokamoto@jp.fujitsu.com>,
	Christoffer Dall <cdall@kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Zhang Lei <zhang.lei@jp.fujitsu.com>,
	Julien Grall <julien.grall@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 12/14] KVM: Clarify capability requirements for KVM_ARM_VCPU_FINALIZE
Date: Fri, 12 Apr 2019 17:28:16 +0100	[thread overview]
Message-ID: <1555086498-26691-13-git-send-email-Dave.Martin@arm.com> (raw)
Message-ID: <20190412162816.4wLYBagr8SxfT59JNQ_XK63WDUVbmtAVWCJ7JaUKNbM@z> (raw)
In-Reply-To: <1555086498-26691-1-git-send-email-Dave.Martin@arm.com>

Userspace is only supposed to use KVM_ARM_VCPU_FINALIZE when there
is some vcpu feature that can actually be finalized.

This means that documenting KVM_ARM_VCPU_FINALIZE as available or
not depending on the capabilities present is not helpful.

This patch amends the documentation to describe availability in
terms of which capability is required for each finalizable feature
instead.

In any case, userspace sees the same error (EINVAL) regardless of
whether the given feature is not present or KVM_ARM_VCPU_FINALIZE
is not implemented at all.

No functional change.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
 Documentation/virtual/kvm/api.txt | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 68509de..b115b23 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3997,17 +3997,16 @@ userspace should not expect to get any particular value there.
 
 4.119 KVM_ARM_VCPU_FINALIZE
 
-Capability: KVM_CAP_ARM_SVE
 Architectures: arm, arm64
 Type: vcpu ioctl
 Parameters: int feature (in)
 Returns: 0 on success, -1 on error
 Errors:
   EPERM:     feature not enabled, needs configuration, or already finalized
-  EINVAL:    unknown feature
+  EINVAL:    feature unknown or not present
 
 Recognised values for feature:
-  arm64      KVM_ARM_VCPU_SVE
+  arm64      KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE)
 
 Finalizes the configuration of the specified vcpu feature.
 
-- 
2.1.4

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  parent reply	other threads:[~2019-04-12 16:29 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-12 16:28 [PATCH 00/14] KVM: arm64: SVE cleanups Dave Martin
2019-04-12 16:28 ` Dave Martin
2019-04-12 16:28 ` [PATCH 01/14] arm64/sve: Clarify vq map semantics Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 02/14] KVM: arm/arm64: Demote kvm_arm_init_arch_resources() to just set up SVE Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 03/14] KVM: arm: Make vcpu finalization stubs into inline functions Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 04/14] KVM: arm64/sve: sys_regs: Demote redundant vcpu_has_sve() checks to WARNs Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 05/14] KVM: arm64/sve: Clean up UAPI register ID definitions Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-15 15:17   ` Andrew Jones
2019-04-15 15:17     ` Andrew Jones
2019-04-16 12:37     ` Dave Martin
2019-04-16 12:37       ` Dave Martin
2019-04-12 16:28 ` [PATCH 06/14] KVM: arm64/sve: Miscellaneous tidyups in guest.c Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 07/14] KVM: arm64/sve: Make register ioctl access errors more consistent Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 08/14] KVM: arm64/sve: WARN when avoiding divide-by-zero in sve_reg_to_region() Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 09/14] KVM: arm64/sve: Simplify KVM_REG_ARM64_SVE_VLS array sizing Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-15 15:20   ` Andrew Jones
2019-04-15 15:20     ` Andrew Jones
2019-04-16 12:41     ` Dave Martin
2019-04-16 12:41       ` Dave Martin
2019-04-16 13:00       ` Andrew Jones
2019-04-16 13:00         ` Andrew Jones
2019-04-16 14:10         ` Dave Martin
2019-04-16 14:10           ` Dave Martin
2019-04-16 14:28           ` Andrew Jones
2019-04-16 14:28             ` Andrew Jones
2019-04-16 15:36             ` Dave Martin
2019-04-16 15:36               ` Dave Martin
2019-04-16 15:52             ` Dave Martin
2019-04-16 15:52               ` Dave Martin
2019-04-17  4:16               ` Andrew Jones
2019-04-17  4:16                 ` Andrew Jones
2019-04-17 14:01                 ` Dave Martin
2019-04-17 14:01                   ` Dave Martin
2019-04-12 16:28 ` [PATCH 10/14] KVM: arm64/sve: Explain validity checks in set_sve_vls() Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` [PATCH 11/14] KVM: arm/arm64: Clean up vcpu finalization function parameter naming Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-12 16:28 ` Dave Martin [this message]
2019-04-12 16:28   ` [PATCH 12/14] KVM: Clarify capability requirements for KVM_ARM_VCPU_FINALIZE Dave Martin
2019-04-12 16:28 ` [PATCH 13/14] KVM: Clarify KVM_{SET, GET}_ONE_REG error code documentation Dave Martin
2019-04-15 15:21   ` [PATCH 13/14] KVM: Clarify KVM_{SET,GET}_ONE_REG " Andrew Jones
2019-04-15 15:21     ` Andrew Jones
2019-04-16 12:42     ` Dave Martin
2019-04-16 12:42       ` Dave Martin
2019-04-12 16:28 ` [PATCH 14/14] KVM: arm64: Clarify access behaviour for out-of-range SVE register slice IDs Dave Martin
2019-04-12 16:28   ` Dave Martin
2019-04-15 15:22 ` [PATCH 00/14] KVM: arm64: SVE cleanups Andrew Jones
2019-04-15 15:22   ` Andrew Jones
2019-04-16 12:46   ` Dave Martin
2019-04-16 12:46     ` Dave Martin

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