* [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest
@ 2013-12-12 16:12 Anup Patel
2013-12-12 16:12 ` [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions Anup Patel
` (6 more replies)
0 siblings, 7 replies; 16+ messages in thread
From: Anup Patel @ 2013-12-12 16:12 UTC (permalink / raw)
To: linux-arm-kernel
Current max VCPUs per-Guest is set to 4 which is preventing
us from creating a Guest (or VM) with 8 VCPUs on Host (e.g.
X-Gene Storm SOC) with 8 Host CPUs.
The correct value of max VCPUs per-Guest should be same as
the max CPUs supported by GICv2 which is 8 but, increasing
value of max VCPUs per-Guest can make things slower hence
we add Kconfig option to let KVM users select appropriate
max VCPUs per-Guest.
Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
---
arch/arm64/include/asm/kvm_host.h | 7 ++++++-
arch/arm64/kvm/Kconfig | 11 +++++++++++
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 5d85a02..0a1d697 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -26,7 +26,12 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_mmio.h>
-#define KVM_MAX_VCPUS 4
+#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
+#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
+#else
+#define KVM_MAX_VCPUS 0
+#endif
+
#define KVM_USER_MEM_SLOTS 32
#define KVM_PRIVATE_MEM_SLOTS 4
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 4480ab3..8ba85e9 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -36,6 +36,17 @@ config KVM_ARM_HOST
---help---
Provides host support for ARM processors.
+config KVM_ARM_MAX_VCPUS
+ int "Number maximum supported virtual CPUs per VM"
+ depends on KVM_ARM_HOST
+ default 4
+ help
+ Static number of max supported virtual CPUs per VM.
+
+ If you choose a high number, the vcpu structures will be quite
+ large, so only choose a reasonable number that you expect to
+ actually use.
+
config KVM_ARM_VGIC
bool
depends on KVM_ARM_HOST && OF
--
1.7.9.5
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
@ 2013-12-12 16:12 ` Anup Patel
2013-12-13 17:36 ` Marc Zyngier
2013-12-13 19:16 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH] KVM: Documentation: Fix typo for KVM_ARM_VCPU_INIT ioctl Anup Patel
` (5 subsequent siblings)
6 siblings, 2 replies; 16+ messages in thread
From: Anup Patel @ 2013-12-12 16:12 UTC (permalink / raw)
To: linux-arm-kernel
The SMC-based PSCI emulation for Guest is going to be very different
from the in-kernel HVC-based PSCI emulation hence for now just inject
undefined exception when Guest executes SMC instruction.
Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
---
arch/arm64/kvm/handle_exit.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 8da5606..df84d7b 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -39,9 +39,6 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
- if (kvm_psci_call(vcpu))
- return 1;
-
kvm_inject_undefined(vcpu);
return 1;
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH] KVM: Documentation: Fix typo for KVM_ARM_VCPU_INIT ioctl
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
2013-12-12 16:12 ` [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions Anup Patel
@ 2013-12-12 16:12 ` Anup Patel
2013-12-13 19:18 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH v2 0/2] PSCI system off and reset for KVM ARM/ARM64 Anup Patel
` (4 subsequent siblings)
6 siblings, 1 reply; 16+ messages in thread
From: Anup Patel @ 2013-12-12 16:12 UTC (permalink / raw)
To: linux-arm-kernel
Fix minor typo in "Parameters:" of KVM_ARM_VCPU_INIT documentation.
Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
---
Documentation/virtual/kvm/api.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index a30035d..aad3244 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2327,7 +2327,7 @@ current state. "addr" is ignored.
Capability: basic
Architectures: arm, arm64
Type: vcpu ioctl
-Parameters: struct struct kvm_vcpu_init (in)
+Parameters: struct kvm_vcpu_init (in)
Returns: 0 on success; -1 on error
Errors:
?EINVAL: ???the target is unknown, or the combination of features is invalid.
--
1.7.9.5
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH v2 0/2] PSCI system off and reset for KVM ARM/ARM64
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
2013-12-12 16:12 ` [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions Anup Patel
2013-12-12 16:12 ` [PATCH] KVM: Documentation: Fix typo for KVM_ARM_VCPU_INIT ioctl Anup Patel
@ 2013-12-12 16:12 ` Anup Patel
2013-12-13 19:19 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH v2 1/2] KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header Anup Patel
` (3 subsequent siblings)
6 siblings, 1 reply; 16+ messages in thread
From: Anup Patel @ 2013-12-12 16:12 UTC (permalink / raw)
To: linux-arm-kernel
The Power State and Coordination Interface (PSCI) specification defines
SYSTEM_OFF and SYSTEM_RESET functions for system poweroff and reboot.
This patchset adds emulation of PSCI SYSTEM_OFF and SYSTEM_RESET functions
in KVM ARM/ARM64 by forwarding them to user space (QEMU or KVMTOOL) using
KVM_EXIT_SYSTEM_EVENT exit reason.
To try this patch from guest kernel, we will need PSCI-based restart and
poweroff support in the guest kenel for both ARM and ARM64.
Rob Herring has already submitted patches for PSCI-based restart and
poweroff in ARM kernel but these are not merged yet due unstable device
tree bindings of kernel PSCI support. We will be having similar patches
for PSCI-based restart and poweroff in ARM64 kernel.
(Refer http://www.spinics.net/lists/arm-kernel/msg262217.html)
(Refer http://www.spinics.net/lists/devicetree/msg05348.html)
Change Log:
V2:
- Replace KVM_EXIT_RESET with KVM_EXIT_SYSTEM_EVENT
- Make kvm_psci_call() return convention to match
KVM ARM return convention
V1:
- Initial revised patch after RFC PATCH.
Anup Patel (2):
KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header
ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user
space
Documentation/virtual/kvm/api.txt | 15 ++++++++++++
arch/arm/include/asm/kvm_psci.h | 2 +-
arch/arm/include/uapi/asm/kvm.h | 2 ++
arch/arm/kvm/handle_exit.c | 13 +++++++---
arch/arm/kvm/psci.c | 48 ++++++++++++++++++++++++++++++-------
arch/arm64/include/asm/kvm_psci.h | 2 +-
arch/arm64/include/uapi/asm/kvm.h | 2 ++
arch/arm64/kvm/handle_exit.c | 12 +++++++---
include/uapi/linux/kvm.h | 8 +++++++
9 files changed, 88 insertions(+), 16 deletions(-)
--
1.7.9.5
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v2 1/2] KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
` (2 preceding siblings ...)
2013-12-12 16:12 ` [PATCH v2 0/2] PSCI system off and reset for KVM ARM/ARM64 Anup Patel
@ 2013-12-12 16:12 ` Anup Patel
2013-12-13 19:22 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space Anup Patel
` (2 subsequent siblings)
6 siblings, 1 reply; 16+ messages in thread
From: Anup Patel @ 2013-12-12 16:12 UTC (permalink / raw)
To: linux-arm-kernel
Currently, we don't have an exit reason to notify user space about
a system-level event (for e.g. system reset or shutdown) triggered
by the VCPU. This patch adds exit reason KVM_EXIT_SYSTEM_EVENT for
this purpose. We can also inform user space about the 'type' and
architecture specific 'flags' of a system-level event using the
kvm_run structure.
This newly added KVM_EXIT_SYSTEM_EVENT will be used by KVM arm/arm64
in-kernel PSCI support to reset/shutdown VMs.
Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
---
Documentation/virtual/kvm/api.txt | 15 +++++++++++++++
include/uapi/linux/kvm.h | 8 ++++++++
2 files changed, 23 insertions(+)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index aad3244..4ef180e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2699,6 +2699,21 @@ It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an
external interrupt has just been delivered into the guest. User space
should put the acknowledged interrupt vector into the 'epr' field.
+ /* KVM_EXIT_SYSTEM_EVENT */
+ struct {
+#define KVM_SYSTEM_EVENT_SHUTDOWN 1
+#define KVM_SYSTEM_EVENT_RESET 2
+ __u32 type;
+ __u64 flags;
+ } system_event;
+
+If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered
+a system-level event using some architecture specific mechanism (hypercall
+or some special instruction). In case of ARM/ARM64, this is triggered using
+HVC instruction based PSCI call from the vcpu. The 'type' field describes
+the system-level event type. The 'flags' field describes architecture
+specific flags for the system-level event.
+
/* Fix the size of the union. */
char padding[256];
};
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 902f124..bb13faa 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -171,6 +171,7 @@ struct kvm_pit_config {
#define KVM_EXIT_WATCHDOG 21
#define KVM_EXIT_S390_TSCH 22
#define KVM_EXIT_EPR 23
+#define KVM_EXIT_SYSTEM_EVENT 24
/* For KVM_EXIT_INTERNAL_ERROR */
/* Emulate instruction failed. */
@@ -301,6 +302,13 @@ struct kvm_run {
struct {
__u32 epr;
} epr;
+ /* KVM_EXIT_SYSTEM_EVENT */
+ struct {
+#define KVM_SYSTEM_EVENT_SHUTDOWN 1
+#define KVM_SYSTEM_EVENT_RESET 2
+ __u32 type;
+ __u64 flags;
+ } system_event;
/* Fix the size of the union. */
char padding[256];
};
--
1.7.9.5
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
` (3 preceding siblings ...)
2013-12-12 16:12 ` [PATCH v2 1/2] KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header Anup Patel
@ 2013-12-12 16:12 ` Anup Patel
2013-12-13 20:08 ` Christoffer Dall
2013-12-13 17:35 ` [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Marc Zyngier
2013-12-13 19:17 ` Christoffer Dall
6 siblings, 1 reply; 16+ messages in thread
From: Anup Patel @ 2013-12-12 16:12 UTC (permalink / raw)
To: linux-arm-kernel
The PSCI SYSTEM_OFF and SYSTEM_RESET functions are system-level
functions hence cannot be fully emulated by the in-kernel PSCI
emulation code.
To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function
calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run
structure using KVM_EXIT_SYSTEM_EVENT exit reasons.
Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
---
arch/arm/include/asm/kvm_psci.h | 2 +-
arch/arm/include/uapi/asm/kvm.h | 2 ++
arch/arm/kvm/handle_exit.c | 13 +++++++---
arch/arm/kvm/psci.c | 48 ++++++++++++++++++++++++++++++-------
arch/arm64/include/asm/kvm_psci.h | 2 +-
arch/arm64/include/uapi/asm/kvm.h | 2 ++
arch/arm64/kvm/handle_exit.c | 12 +++++++---
7 files changed, 65 insertions(+), 16 deletions(-)
diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
index 9a83d98..992d7f1 100644
--- a/arch/arm/include/asm/kvm_psci.h
+++ b/arch/arm/include/asm/kvm_psci.h
@@ -18,6 +18,6 @@
#ifndef __ARM_KVM_PSCI_H__
#define __ARM_KVM_PSCI_H__
-bool kvm_psci_call(struct kvm_vcpu *vcpu);
+int kvm_psci_call(struct kvm_vcpu *vcpu);
#endif /* __ARM_KVM_PSCI_H__ */
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index c498b60..f4de20c 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -172,6 +172,8 @@ struct kvm_arch_memory_slot {
#define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
#define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
#define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
+#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
+#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
#define KVM_PSCI_RET_SUCCESS 0
#define KVM_PSCI_RET_NI ((unsigned long)-1)
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index a920790..c3f0e72 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -40,14 +40,21 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
+ int ret;
+
trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
kvm_vcpu_hvc_get_imm(vcpu));
- if (kvm_psci_call(vcpu))
+ ret = kvm_psci_call(vcpu);
+ if (ret >= 0)
+ return ret;
+ else if (ret == -EINVAL) {
+ kvm_inject_undefined(vcpu);
return 1;
+ }
+
+ return ret;
- kvm_inject_undefined(vcpu);
- return 1;
}
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
index 0881bf1..8e246d6 100644
--- a/arch/arm/kvm/psci.c
+++ b/arch/arm/kvm/psci.c
@@ -84,18 +84,41 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
return KVM_PSCI_RET_SUCCESS;
}
+static inline void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
+{
+ memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
+ vcpu->run->system_event.type = type;
+ vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
+}
+
+static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
+{
+ kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
+}
+
+static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
+{
+ kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
+}
+
/**
* kvm_psci_call - handle PSCI call if r0 value is in range
* @vcpu: Pointer to the VCPU struct
*
* Handle PSCI calls from guests through traps from HVC instructions.
- * The calling convention is similar to SMC calls to the secure world where
- * the function number is placed in r0 and this function returns true if the
- * function number specified in r0 is withing the PSCI range, and false
- * otherwise.
+ * The calling convention is similar to SMC calls to the secure world
+ * where the function number is placed in r0 and function number
+ * specified in r0 is withing the PSCI range.
+ *
+ * This function returns: > 0 (success), 0 (success but exit to user
+ * space), and < 0 (errors)
+ *
+ * Errors:
+ * -EINVAL: Unrecognized PSCI function
*/
-bool kvm_psci_call(struct kvm_vcpu *vcpu)
+int kvm_psci_call(struct kvm_vcpu *vcpu)
{
+ int ret = 1;
unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
unsigned long val;
@@ -111,11 +134,20 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu)
case KVM_PSCI_FN_MIGRATE:
val = KVM_PSCI_RET_NI;
break;
-
+ case KVM_PSCI_FN_SYSTEM_OFF:
+ kvm_psci_system_off(vcpu);
+ val = KVM_PSCI_RET_SUCCESS;
+ ret = 0;
+ break;
+ case KVM_PSCI_FN_SYSTEM_RESET:
+ kvm_psci_system_reset(vcpu);
+ val = KVM_PSCI_RET_SUCCESS;
+ ret = 0;
+ break;
default:
- return false;
+ return -EINVAL;
}
*vcpu_reg(vcpu, 0) = val;
- return true;
+ return ret;
}
diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h
index e301a48..9bd0ee8 100644
--- a/arch/arm64/include/asm/kvm_psci.h
+++ b/arch/arm64/include/asm/kvm_psci.h
@@ -18,6 +18,6 @@
#ifndef __ARM64_KVM_PSCI_H__
#define __ARM64_KVM_PSCI_H__
-bool kvm_psci_call(struct kvm_vcpu *vcpu);
+int kvm_psci_call(struct kvm_vcpu *vcpu);
#endif /* __ARM64_KVM_PSCI_H__ */
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index d9f026b..f678902 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -158,6 +158,8 @@ struct kvm_arch_memory_slot {
#define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
#define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
#define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
+#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
+#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
#define KVM_PSCI_RET_SUCCESS 0
#define KVM_PSCI_RET_NI ((unsigned long)-1)
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index df84d7b..e382eb8 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -30,11 +30,17 @@ typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
- if (kvm_psci_call(vcpu))
+ int ret;
+
+ ret = kvm_psci_call(vcpu);
+ if (ret >= 0)
+ return ret;
+ else if (ret == -EINVAL) {
+ kvm_inject_undefined(vcpu);
return 1;
+ }
- kvm_inject_undefined(vcpu);
- return 1;
+ return ret;
}
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
--
1.7.9.5
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
` (4 preceding siblings ...)
2013-12-12 16:12 ` [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space Anup Patel
@ 2013-12-13 17:35 ` Marc Zyngier
2013-12-13 19:17 ` Christoffer Dall
6 siblings, 0 replies; 16+ messages in thread
From: Marc Zyngier @ 2013-12-13 17:35 UTC (permalink / raw)
To: linux-arm-kernel
On 12/12/13 16:12, Anup Patel wrote:
> Current max VCPUs per-Guest is set to 4 which is preventing
> us from creating a Guest (or VM) with 8 VCPUs on Host (e.g.
> X-Gene Storm SOC) with 8 Host CPUs.
>
> The correct value of max VCPUs per-Guest should be same as
> the max CPUs supported by GICv2 which is 8 but, increasing
> value of max VCPUs per-Guest can make things slower hence
> we add Kconfig option to let KVM users select appropriate
> max VCPUs per-Guest.
>
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
M.
> ---
> arch/arm64/include/asm/kvm_host.h | 7 ++++++-
> arch/arm64/kvm/Kconfig | 11 +++++++++++
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 5d85a02..0a1d697 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -26,7 +26,12 @@
> #include <asm/kvm_asm.h>
> #include <asm/kvm_mmio.h>
>
> -#define KVM_MAX_VCPUS 4
> +#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
> +#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
> +#else
> +#define KVM_MAX_VCPUS 0
> +#endif
> +
> #define KVM_USER_MEM_SLOTS 32
> #define KVM_PRIVATE_MEM_SLOTS 4
> #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> index 4480ab3..8ba85e9 100644
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -36,6 +36,17 @@ config KVM_ARM_HOST
> ---help---
> Provides host support for ARM processors.
>
> +config KVM_ARM_MAX_VCPUS
> + int "Number maximum supported virtual CPUs per VM"
> + depends on KVM_ARM_HOST
> + default 4
> + help
> + Static number of max supported virtual CPUs per VM.
> +
> + If you choose a high number, the vcpu structures will be quite
> + large, so only choose a reasonable number that you expect to
> + actually use.
> +
> config KVM_ARM_VGIC
> bool
> depends on KVM_ARM_HOST && OF
>
--
Jazz is not dead. It just smells funny...
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions
2013-12-12 16:12 ` [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions Anup Patel
@ 2013-12-13 17:36 ` Marc Zyngier
2013-12-13 19:16 ` Christoffer Dall
1 sibling, 0 replies; 16+ messages in thread
From: Marc Zyngier @ 2013-12-13 17:36 UTC (permalink / raw)
To: linux-arm-kernel
On 12/12/13 16:12, Anup Patel wrote:
> The SMC-based PSCI emulation for Guest is going to be very different
> from the in-kernel HVC-based PSCI emulation hence for now just inject
> undefined exception when Guest executes SMC instruction.
>
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
M.
> ---
> arch/arm64/kvm/handle_exit.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 8da5606..df84d7b 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -39,9 +39,6 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> - if (kvm_psci_call(vcpu))
> - return 1;
> -
> kvm_inject_undefined(vcpu);
> return 1;
> }
>
--
Jazz is not dead. It just smells funny...
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions
2013-12-12 16:12 ` [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions Anup Patel
2013-12-13 17:36 ` Marc Zyngier
@ 2013-12-13 19:16 ` Christoffer Dall
1 sibling, 0 replies; 16+ messages in thread
From: Christoffer Dall @ 2013-12-13 19:16 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Dec 12, 2013 at 09:42:23PM +0530, Anup Patel wrote:
> The SMC-based PSCI emulation for Guest is going to be very different
> from the in-kernel HVC-based PSCI emulation hence for now just inject
> undefined exception when Guest executes SMC instruction.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
>
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> ---
> arch/arm64/kvm/handle_exit.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 8da5606..df84d7b 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -39,9 +39,6 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> - if (kvm_psci_call(vcpu))
> - return 1;
> -
> kvm_inject_undefined(vcpu);
> return 1;
> }
> --
> 1.7.9.5
>
--
Christoffer
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
` (5 preceding siblings ...)
2013-12-13 17:35 ` [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Marc Zyngier
@ 2013-12-13 19:17 ` Christoffer Dall
6 siblings, 0 replies; 16+ messages in thread
From: Christoffer Dall @ 2013-12-13 19:17 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Dec 12, 2013 at 09:42:22PM +0530, Anup Patel wrote:
> Current max VCPUs per-Guest is set to 4 which is preventing
> us from creating a Guest (or VM) with 8 VCPUs on Host (e.g.
> X-Gene Storm SOC) with 8 Host CPUs.
>
> The correct value of max VCPUs per-Guest should be same as
> the max CPUs supported by GICv2 which is 8 but, increasing
> value of max VCPUs per-Guest can make things slower hence
> we add Kconfig option to let KVM users select appropriate
> max VCPUs per-Guest.
>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> ---
> arch/arm64/include/asm/kvm_host.h | 7 ++++++-
> arch/arm64/kvm/Kconfig | 11 +++++++++++
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 5d85a02..0a1d697 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -26,7 +26,12 @@
> #include <asm/kvm_asm.h>
> #include <asm/kvm_mmio.h>
>
> -#define KVM_MAX_VCPUS 4
> +#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
> +#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
> +#else
> +#define KVM_MAX_VCPUS 0
> +#endif
> +
> #define KVM_USER_MEM_SLOTS 32
> #define KVM_PRIVATE_MEM_SLOTS 4
> #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> index 4480ab3..8ba85e9 100644
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -36,6 +36,17 @@ config KVM_ARM_HOST
> ---help---
> Provides host support for ARM processors.
>
> +config KVM_ARM_MAX_VCPUS
> + int "Number maximum supported virtual CPUs per VM"
> + depends on KVM_ARM_HOST
> + default 4
> + help
> + Static number of max supported virtual CPUs per VM.
> +
> + If you choose a high number, the vcpu structures will be quite
> + large, so only choose a reasonable number that you expect to
> + actually use.
> +
> config KVM_ARM_VGIC
> bool
> depends on KVM_ARM_HOST && OF
> --
> 1.7.9.5
>
--
Christoffer
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH] KVM: Documentation: Fix typo for KVM_ARM_VCPU_INIT ioctl
2013-12-12 16:12 ` [PATCH] KVM: Documentation: Fix typo for KVM_ARM_VCPU_INIT ioctl Anup Patel
@ 2013-12-13 19:18 ` Christoffer Dall
0 siblings, 0 replies; 16+ messages in thread
From: Christoffer Dall @ 2013-12-13 19:18 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Dec 12, 2013 at 09:42:24PM +0530, Anup Patel wrote:
> Fix minor typo in "Parameters:" of KVM_ARM_VCPU_INIT documentation.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
>
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> ---
> Documentation/virtual/kvm/api.txt | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index a30035d..aad3244 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -2327,7 +2327,7 @@ current state. "addr" is ignored.
> Capability: basic
> Architectures: arm, arm64
> Type: vcpu ioctl
> -Parameters: struct struct kvm_vcpu_init (in)
> +Parameters: struct kvm_vcpu_init (in)
> Returns: 0 on success; -1 on error
> Errors:
> ?EINVAL: ???the target is unknown, or the combination of features is invalid.
> --
> 1.7.9.5
>
--
Christoffer
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v2 0/2] PSCI system off and reset for KVM ARM/ARM64
2013-12-12 16:12 ` [PATCH v2 0/2] PSCI system off and reset for KVM ARM/ARM64 Anup Patel
@ 2013-12-13 19:19 ` Christoffer Dall
0 siblings, 0 replies; 16+ messages in thread
From: Christoffer Dall @ 2013-12-13 19:19 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Dec 12, 2013 at 09:42:25PM +0530, Anup Patel wrote:
> The Power State and Coordination Interface (PSCI) specification defines
> SYSTEM_OFF and SYSTEM_RESET functions for system poweroff and reboot.
>
> This patchset adds emulation of PSCI SYSTEM_OFF and SYSTEM_RESET functions
> in KVM ARM/ARM64 by forwarding them to user space (QEMU or KVMTOOL) using
> KVM_EXIT_SYSTEM_EVENT exit reason.
>
> To try this patch from guest kernel, we will need PSCI-based restart and
> poweroff support in the guest kenel for both ARM and ARM64.
>
> Rob Herring has already submitted patches for PSCI-based restart and
> poweroff in ARM kernel but these are not merged yet due unstable device
> tree bindings of kernel PSCI support. We will be having similar patches
> for PSCI-based restart and poweroff in ARM64 kernel.
> (Refer http://www.spinics.net/lists/arm-kernel/msg262217.html)
> (Refer http://www.spinics.net/lists/devicetree/msg05348.html)
There's something really funky about the threading and reply-to settings
of all of these patches, please check your e-mail sending tool config.
>
> Change Log:
>
> V2:
> - Replace KVM_EXIT_RESET with KVM_EXIT_SYSTEM_EVENT
> - Make kvm_psci_call() return convention to match
> KVM ARM return convention
>
> V1:
> - Initial revised patch after RFC PATCH.
>
> Anup Patel (2):
> KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header
> ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user
> space
>
> Documentation/virtual/kvm/api.txt | 15 ++++++++++++
> arch/arm/include/asm/kvm_psci.h | 2 +-
> arch/arm/include/uapi/asm/kvm.h | 2 ++
> arch/arm/kvm/handle_exit.c | 13 +++++++---
> arch/arm/kvm/psci.c | 48 ++++++++++++++++++++++++++++++-------
> arch/arm64/include/asm/kvm_psci.h | 2 +-
> arch/arm64/include/uapi/asm/kvm.h | 2 ++
> arch/arm64/kvm/handle_exit.c | 12 +++++++---
> include/uapi/linux/kvm.h | 8 +++++++
> 9 files changed, 88 insertions(+), 16 deletions(-)
>
> --
> 1.7.9.5
>
--
Christoffer
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v2 1/2] KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header
2013-12-12 16:12 ` [PATCH v2 1/2] KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header Anup Patel
@ 2013-12-13 19:22 ` Christoffer Dall
0 siblings, 0 replies; 16+ messages in thread
From: Christoffer Dall @ 2013-12-13 19:22 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Dec 12, 2013 at 09:42:26PM +0530, Anup Patel wrote:
> Currently, we don't have an exit reason to notify user space about
> a system-level event (for e.g. system reset or shutdown) triggered
> by the VCPU. This patch adds exit reason KVM_EXIT_SYSTEM_EVENT for
> this purpose. We can also inform user space about the 'type' and
> architecture specific 'flags' of a system-level event using the
> kvm_run structure.
>
> This newly added KVM_EXIT_SYSTEM_EVENT will be used by KVM arm/arm64
> in-kernel PSCI support to reset/shutdown VMs.
>
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> ---
> Documentation/virtual/kvm/api.txt | 15 +++++++++++++++
> include/uapi/linux/kvm.h | 8 ++++++++
> 2 files changed, 23 insertions(+)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index aad3244..4ef180e 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -2699,6 +2699,21 @@ It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an
> external interrupt has just been delivered into the guest. User space
> should put the acknowledged interrupt vector into the 'epr' field.
>
> + /* KVM_EXIT_SYSTEM_EVENT */
> + struct {
> +#define KVM_SYSTEM_EVENT_SHUTDOWN 1
> +#define KVM_SYSTEM_EVENT_RESET 2
> + __u32 type;
> + __u64 flags;
> + } system_event;
> +
> +If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered
> +a system-level event using some architecture specific mechanism (hypercall
> +or some special instruction). In case of ARM/ARM64, this is triggered using
> +HVC instruction based PSCI call from the vcpu. The 'type' field describes
> +the system-level event type. The 'flags' field describes architecture
> +specific flags for the system-level event.
> +
> /* Fix the size of the union. */
> char padding[256];
> };
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 902f124..bb13faa 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -171,6 +171,7 @@ struct kvm_pit_config {
> #define KVM_EXIT_WATCHDOG 21
> #define KVM_EXIT_S390_TSCH 22
> #define KVM_EXIT_EPR 23
> +#define KVM_EXIT_SYSTEM_EVENT 24
>
> /* For KVM_EXIT_INTERNAL_ERROR */
> /* Emulate instruction failed. */
> @@ -301,6 +302,13 @@ struct kvm_run {
> struct {
> __u32 epr;
> } epr;
> + /* KVM_EXIT_SYSTEM_EVENT */
> + struct {
> +#define KVM_SYSTEM_EVENT_SHUTDOWN 1
> +#define KVM_SYSTEM_EVENT_RESET 2
> + __u32 type;
> + __u64 flags;
> + } system_event;
> /* Fix the size of the union. */
> char padding[256];
> };
> --
> 1.7.9.5
>
Looks good to me:
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space
2013-12-12 16:12 ` [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space Anup Patel
@ 2013-12-13 20:08 ` Christoffer Dall
2013-12-14 13:24 ` Anup Patel
0 siblings, 1 reply; 16+ messages in thread
From: Christoffer Dall @ 2013-12-13 20:08 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Dec 12, 2013 at 09:42:27PM +0530, Anup Patel wrote:
> The PSCI SYSTEM_OFF and SYSTEM_RESET functions are system-level
> functions hence cannot be fully emulated by the in-kernel PSCI
> emulation code.
>
> To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function
> calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run
> structure using KVM_EXIT_SYSTEM_EVENT exit reasons.
>
> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> ---
> arch/arm/include/asm/kvm_psci.h | 2 +-
> arch/arm/include/uapi/asm/kvm.h | 2 ++
> arch/arm/kvm/handle_exit.c | 13 +++++++---
> arch/arm/kvm/psci.c | 48 ++++++++++++++++++++++++++++++-------
> arch/arm64/include/asm/kvm_psci.h | 2 +-
> arch/arm64/include/uapi/asm/kvm.h | 2 ++
> arch/arm64/kvm/handle_exit.c | 12 +++++++---
> 7 files changed, 65 insertions(+), 16 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
> index 9a83d98..992d7f1 100644
> --- a/arch/arm/include/asm/kvm_psci.h
> +++ b/arch/arm/include/asm/kvm_psci.h
> @@ -18,6 +18,6 @@
> #ifndef __ARM_KVM_PSCI_H__
> #define __ARM_KVM_PSCI_H__
>
> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>
> #endif /* __ARM_KVM_PSCI_H__ */
> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> index c498b60..f4de20c 100644
> --- a/arch/arm/include/uapi/asm/kvm.h
> +++ b/arch/arm/include/uapi/asm/kvm.h
> @@ -172,6 +172,8 @@ struct kvm_arch_memory_slot {
> #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
> #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
> #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
> +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
> +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
>
> #define KVM_PSCI_RET_SUCCESS 0
> #define KVM_PSCI_RET_NI ((unsigned long)-1)
> diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
> index a920790..c3f0e72 100644
> --- a/arch/arm/kvm/handle_exit.c
> +++ b/arch/arm/kvm/handle_exit.c
> @@ -40,14 +40,21 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> + int ret;
> +
> trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
> kvm_vcpu_hvc_get_imm(vcpu));
>
> - if (kvm_psci_call(vcpu))
> + ret = kvm_psci_call(vcpu);
> + if (ret >= 0)
> + return ret;
> + else if (ret == -EINVAL) {
> + kvm_inject_undefined(vcpu);
> return 1;
> + }
> +
> + return ret;
Wouldn't
ret = kvm_psci_call(vcpu);
if (ret == -EINVAL) {
kvm_inject_undefined(vcpu);
return 1;
}
return ret;
be simpler?
also, minor nit, but I think according to the CodingStyle if you have
single statements in if cases, but they are part of a larger if
statement with alternative clauses that use curly-brackets to
encapsulate multiple statements, then you should use curly braces around
the single-line statement as well...
>
> - kvm_inject_undefined(vcpu);
> - return 1;
> }
>
> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
> index 0881bf1..8e246d6 100644
> --- a/arch/arm/kvm/psci.c
> +++ b/arch/arm/kvm/psci.c
> @@ -84,18 +84,41 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> return KVM_PSCI_RET_SUCCESS;
> }
>
> +static inline void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
> +{
> + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
> + vcpu->run->system_event.type = type;
> + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
> +}
> +
> +static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
> +{
> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
> +}
> +
> +static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
> +{
> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
> +}
> +
> /**
> * kvm_psci_call - handle PSCI call if r0 value is in range
> * @vcpu: Pointer to the VCPU struct
> *
> * Handle PSCI calls from guests through traps from HVC instructions.
> - * The calling convention is similar to SMC calls to the secure world where
> - * the function number is placed in r0 and this function returns true if the
> - * function number specified in r0 is withing the PSCI range, and false
> - * otherwise.
> + * The calling convention is similar to SMC calls to the secure world
> + * where the function number is placed in r0 and function number
the function number
> + * specified in r0 is withing the PSCI range.
this reads a little funny now. I think you can get rid of everything
after the first mention of r0 (cut from "and function number...") since
you explain that in the error codes below.
> + *
> + * This function returns: > 0 (success), 0 (success but exit to user
> + * space), and < 0 (errors)
you could use @return: instead of "This function returns", but I'm not
sure if anyone actually cares.
> + *
> + * Errors:
> + * -EINVAL: Unrecognized PSCI function
> */
> -bool kvm_psci_call(struct kvm_vcpu *vcpu)
> +int kvm_psci_call(struct kvm_vcpu *vcpu)
> {
> + int ret = 1;
> unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
> unsigned long val;
>
> @@ -111,11 +134,20 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu)
> case KVM_PSCI_FN_MIGRATE:
> val = KVM_PSCI_RET_NI;
> break;
> -
> + case KVM_PSCI_FN_SYSTEM_OFF:
> + kvm_psci_system_off(vcpu);
> + val = KVM_PSCI_RET_SUCCESS;
> + ret = 0;
> + break;
> + case KVM_PSCI_FN_SYSTEM_RESET:
> + kvm_psci_system_reset(vcpu);
> + val = KVM_PSCI_RET_SUCCESS;
> + ret = 0;
> + break;
> default:
> - return false;
> + return -EINVAL;
> }
>
> *vcpu_reg(vcpu, 0) = val;
> - return true;
> + return ret;
> }
> diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h
> index e301a48..9bd0ee8 100644
> --- a/arch/arm64/include/asm/kvm_psci.h
> +++ b/arch/arm64/include/asm/kvm_psci.h
> @@ -18,6 +18,6 @@
> #ifndef __ARM64_KVM_PSCI_H__
> #define __ARM64_KVM_PSCI_H__
>
> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>
> #endif /* __ARM64_KVM_PSCI_H__ */
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index d9f026b..f678902 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -158,6 +158,8 @@ struct kvm_arch_memory_slot {
> #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
> #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
> #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
> +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
> +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
>
> #define KVM_PSCI_RET_SUCCESS 0
> #define KVM_PSCI_RET_NI ((unsigned long)-1)
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index df84d7b..e382eb8 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -30,11 +30,17 @@ typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
>
> static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> - if (kvm_psci_call(vcpu))
> + int ret;
> +
> + ret = kvm_psci_call(vcpu);
> + if (ret >= 0)
> + return ret;
> + else if (ret == -EINVAL) {
> + kvm_inject_undefined(vcpu);
> return 1;
> + }
>
> - kvm_inject_undefined(vcpu);
> - return 1;
> + return ret;
same as above.
> }
>
> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> --
> 1.7.9.5
>
Aside from the code formatting and commenting above, it looks pretty
good to me.
-Christoffer
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space
2013-12-13 20:08 ` Christoffer Dall
@ 2013-12-14 13:24 ` Anup Patel
2013-12-14 19:28 ` Christoffer Dall
0 siblings, 1 reply; 16+ messages in thread
From: Anup Patel @ 2013-12-14 13:24 UTC (permalink / raw)
To: linux-arm-kernel
On Sat, Dec 14, 2013 at 1:38 AM, Christoffer Dall
<christoffer.dall@linaro.org> wrote:
> On Thu, Dec 12, 2013 at 09:42:27PM +0530, Anup Patel wrote:
>> The PSCI SYSTEM_OFF and SYSTEM_RESET functions are system-level
>> functions hence cannot be fully emulated by the in-kernel PSCI
>> emulation code.
>>
>> To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function
>> calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run
>> structure using KVM_EXIT_SYSTEM_EVENT exit reasons.
>>
>> Signed-off-by: Anup Patel <anup.patel@linaro.org>
>> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
>> ---
>> arch/arm/include/asm/kvm_psci.h | 2 +-
>> arch/arm/include/uapi/asm/kvm.h | 2 ++
>> arch/arm/kvm/handle_exit.c | 13 +++++++---
>> arch/arm/kvm/psci.c | 48 ++++++++++++++++++++++++++++++-------
>> arch/arm64/include/asm/kvm_psci.h | 2 +-
>> arch/arm64/include/uapi/asm/kvm.h | 2 ++
>> arch/arm64/kvm/handle_exit.c | 12 +++++++---
>> 7 files changed, 65 insertions(+), 16 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
>> index 9a83d98..992d7f1 100644
>> --- a/arch/arm/include/asm/kvm_psci.h
>> +++ b/arch/arm/include/asm/kvm_psci.h
>> @@ -18,6 +18,6 @@
>> #ifndef __ARM_KVM_PSCI_H__
>> #define __ARM_KVM_PSCI_H__
>>
>> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
>> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>>
>> #endif /* __ARM_KVM_PSCI_H__ */
>> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
>> index c498b60..f4de20c 100644
>> --- a/arch/arm/include/uapi/asm/kvm.h
>> +++ b/arch/arm/include/uapi/asm/kvm.h
>> @@ -172,6 +172,8 @@ struct kvm_arch_memory_slot {
>> #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
>> #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
>> #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
>> +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
>> +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
>>
>> #define KVM_PSCI_RET_SUCCESS 0
>> #define KVM_PSCI_RET_NI ((unsigned long)-1)
>> diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
>> index a920790..c3f0e72 100644
>> --- a/arch/arm/kvm/handle_exit.c
>> +++ b/arch/arm/kvm/handle_exit.c
>> @@ -40,14 +40,21 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
>>
>> static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> {
>> + int ret;
>> +
>> trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
>> kvm_vcpu_hvc_get_imm(vcpu));
>>
>> - if (kvm_psci_call(vcpu))
>> + ret = kvm_psci_call(vcpu);
>> + if (ret >= 0)
>> + return ret;
>> + else if (ret == -EINVAL) {
>> + kvm_inject_undefined(vcpu);
>> return 1;
>> + }
>> +
>> + return ret;
>
> Wouldn't
>
> ret = kvm_psci_call(vcpu);
> if (ret == -EINVAL) {
> kvm_inject_undefined(vcpu);
> return 1;
> }
>
> return ret;
>
> be simpler?
Yes, I will make this simpler.
>
> also, minor nit, but I think according to the CodingStyle if you have
> single statements in if cases, but they are part of a larger if
> statement with alternative clauses that use curly-brackets to
> encapsulate multiple statements, then you should use curly braces around
> the single-line statement as well...
>
>>
>> - kvm_inject_undefined(vcpu);
>> - return 1;
>> }
>>
>> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
>> index 0881bf1..8e246d6 100644
>> --- a/arch/arm/kvm/psci.c
>> +++ b/arch/arm/kvm/psci.c
>> @@ -84,18 +84,41 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
>> return KVM_PSCI_RET_SUCCESS;
>> }
>>
>> +static inline void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
>> +{
>> + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
>> + vcpu->run->system_event.type = type;
>> + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
>> +}
>> +
>> +static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
>> +{
>> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
>> +}
>> +
>> +static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
>> +{
>> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
>> +}
>> +
>> /**
>> * kvm_psci_call - handle PSCI call if r0 value is in range
>> * @vcpu: Pointer to the VCPU struct
>> *
>> * Handle PSCI calls from guests through traps from HVC instructions.
>> - * The calling convention is similar to SMC calls to the secure world where
>> - * the function number is placed in r0 and this function returns true if the
>> - * function number specified in r0 is withing the PSCI range, and false
>> - * otherwise.
>> + * The calling convention is similar to SMC calls to the secure world
>> + * where the function number is placed in r0 and function number
>
> the function number
>
>> + * specified in r0 is withing the PSCI range.
>
> this reads a little funny now. I think you can get rid of everything
> after the first mention of r0 (cut from "and function number...") since
> you explain that in the error codes below.
Sure, I will update this comment.
>
>> + *
>> + * This function returns: > 0 (success), 0 (success but exit to user
>> + * space), and < 0 (errors)
>
> you could use @return: instead of "This function returns", but I'm not
> sure if anyone actually cares.
Actually, "@returns" is correct way to specify as-per doxygen
comment style for C but I have seen "Returns:" or "Returns" being
used commonly in other parts of kernel. I will replace "The function
returns:" with "Returns:".
>
>> + *
>> + * Errors:
>> + * -EINVAL: Unrecognized PSCI function
>> */
>> -bool kvm_psci_call(struct kvm_vcpu *vcpu)
>> +int kvm_psci_call(struct kvm_vcpu *vcpu)
>> {
>> + int ret = 1;
>> unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
>> unsigned long val;
>>
>> @@ -111,11 +134,20 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu)
>> case KVM_PSCI_FN_MIGRATE:
>> val = KVM_PSCI_RET_NI;
>> break;
>> -
>> + case KVM_PSCI_FN_SYSTEM_OFF:
>> + kvm_psci_system_off(vcpu);
>> + val = KVM_PSCI_RET_SUCCESS;
>> + ret = 0;
>> + break;
>> + case KVM_PSCI_FN_SYSTEM_RESET:
>> + kvm_psci_system_reset(vcpu);
>> + val = KVM_PSCI_RET_SUCCESS;
>> + ret = 0;
>> + break;
>> default:
>> - return false;
>> + return -EINVAL;
>> }
>>
>> *vcpu_reg(vcpu, 0) = val;
>> - return true;
>> + return ret;
>> }
>> diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h
>> index e301a48..9bd0ee8 100644
>> --- a/arch/arm64/include/asm/kvm_psci.h
>> +++ b/arch/arm64/include/asm/kvm_psci.h
>> @@ -18,6 +18,6 @@
>> #ifndef __ARM64_KVM_PSCI_H__
>> #define __ARM64_KVM_PSCI_H__
>>
>> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
>> +int kvm_psci_call(struct kvm_vcpu *vcpu);
>>
>> #endif /* __ARM64_KVM_PSCI_H__ */
>> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
>> index d9f026b..f678902 100644
>> --- a/arch/arm64/include/uapi/asm/kvm.h
>> +++ b/arch/arm64/include/uapi/asm/kvm.h
>> @@ -158,6 +158,8 @@ struct kvm_arch_memory_slot {
>> #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
>> #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
>> #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
>> +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
>> +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
>>
>> #define KVM_PSCI_RET_SUCCESS 0
>> #define KVM_PSCI_RET_NI ((unsigned long)-1)
>> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
>> index df84d7b..e382eb8 100644
>> --- a/arch/arm64/kvm/handle_exit.c
>> +++ b/arch/arm64/kvm/handle_exit.c
>> @@ -30,11 +30,17 @@ typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
>>
>> static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> {
>> - if (kvm_psci_call(vcpu))
>> + int ret;
>> +
>> + ret = kvm_psci_call(vcpu);
>> + if (ret >= 0)
>> + return ret;
>> + else if (ret == -EINVAL) {
>> + kvm_inject_undefined(vcpu);
>> return 1;
>> + }
>>
>> - kvm_inject_undefined(vcpu);
>> - return 1;
>> + return ret;
>
> same as above.
OK.
>
>> }
>>
>> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>> --
>> 1.7.9.5
>>
>
> Aside from the code formatting and commenting above, it looks pretty
> good to me.
>
> -Christoffer
> _______________________________________________
> kvmarm mailing list
> kvmarm at lists.cs.columbia.edu
> https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space
2013-12-14 13:24 ` Anup Patel
@ 2013-12-14 19:28 ` Christoffer Dall
0 siblings, 0 replies; 16+ messages in thread
From: Christoffer Dall @ 2013-12-14 19:28 UTC (permalink / raw)
To: linux-arm-kernel
On Sat, Dec 14, 2013 at 06:54:58PM +0530, Anup Patel wrote:
> On Sat, Dec 14, 2013 at 1:38 AM, Christoffer Dall
> <christoffer.dall@linaro.org> wrote:
> > On Thu, Dec 12, 2013 at 09:42:27PM +0530, Anup Patel wrote:
> >> The PSCI SYSTEM_OFF and SYSTEM_RESET functions are system-level
> >> functions hence cannot be fully emulated by the in-kernel PSCI
> >> emulation code.
> >>
> >> To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function
> >> calls from vcpu to user space (i.e. QEMU or KVMTOOL) via kvm_run
> >> structure using KVM_EXIT_SYSTEM_EVENT exit reasons.
> >>
> >> Signed-off-by: Anup Patel <anup.patel@linaro.org>
> >> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
> >> ---
> >> arch/arm/include/asm/kvm_psci.h | 2 +-
> >> arch/arm/include/uapi/asm/kvm.h | 2 ++
> >> arch/arm/kvm/handle_exit.c | 13 +++++++---
> >> arch/arm/kvm/psci.c | 48 ++++++++++++++++++++++++++++++-------
> >> arch/arm64/include/asm/kvm_psci.h | 2 +-
> >> arch/arm64/include/uapi/asm/kvm.h | 2 ++
> >> arch/arm64/kvm/handle_exit.c | 12 +++++++---
> >> 7 files changed, 65 insertions(+), 16 deletions(-)
> >>
> >> diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
> >> index 9a83d98..992d7f1 100644
> >> --- a/arch/arm/include/asm/kvm_psci.h
> >> +++ b/arch/arm/include/asm/kvm_psci.h
> >> @@ -18,6 +18,6 @@
> >> #ifndef __ARM_KVM_PSCI_H__
> >> #define __ARM_KVM_PSCI_H__
> >>
> >> -bool kvm_psci_call(struct kvm_vcpu *vcpu);
> >> +int kvm_psci_call(struct kvm_vcpu *vcpu);
> >>
> >> #endif /* __ARM_KVM_PSCI_H__ */
> >> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> >> index c498b60..f4de20c 100644
> >> --- a/arch/arm/include/uapi/asm/kvm.h
> >> +++ b/arch/arm/include/uapi/asm/kvm.h
> >> @@ -172,6 +172,8 @@ struct kvm_arch_memory_slot {
> >> #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
> >> #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
> >> #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
> >> +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4)
> >> +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
> >>
> >> #define KVM_PSCI_RET_SUCCESS 0
> >> #define KVM_PSCI_RET_NI ((unsigned long)-1)
> >> diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
> >> index a920790..c3f0e72 100644
> >> --- a/arch/arm/kvm/handle_exit.c
> >> +++ b/arch/arm/kvm/handle_exit.c
> >> @@ -40,14 +40,21 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
> >>
> >> static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> >> {
> >> + int ret;
> >> +
> >> trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
> >> kvm_vcpu_hvc_get_imm(vcpu));
> >>
> >> - if (kvm_psci_call(vcpu))
> >> + ret = kvm_psci_call(vcpu);
> >> + if (ret >= 0)
> >> + return ret;
> >> + else if (ret == -EINVAL) {
> >> + kvm_inject_undefined(vcpu);
> >> return 1;
> >> + }
> >> +
> >> + return ret;
> >
> > Wouldn't
> >
> > ret = kvm_psci_call(vcpu);
> > if (ret == -EINVAL) {
> > kvm_inject_undefined(vcpu);
> > return 1;
> > }
> >
> > return ret;
> >
> > be simpler?
>
> Yes, I will make this simpler.
>
> >
> > also, minor nit, but I think according to the CodingStyle if you have
> > single statements in if cases, but they are part of a larger if
> > statement with alternative clauses that use curly-brackets to
> > encapsulate multiple statements, then you should use curly braces around
> > the single-line statement as well...
> >
> >>
> >> - kvm_inject_undefined(vcpu);
> >> - return 1;
> >> }
> >>
> >> static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
> >> diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
> >> index 0881bf1..8e246d6 100644
> >> --- a/arch/arm/kvm/psci.c
> >> +++ b/arch/arm/kvm/psci.c
> >> @@ -84,18 +84,41 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> >> return KVM_PSCI_RET_SUCCESS;
> >> }
> >>
> >> +static inline void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
> >> +{
> >> + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
> >> + vcpu->run->system_event.type = type;
> >> + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
> >> +}
> >> +
> >> +static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
> >> +{
> >> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
> >> +}
> >> +
> >> +static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
> >> +{
> >> + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
> >> +}
> >> +
> >> /**
> >> * kvm_psci_call - handle PSCI call if r0 value is in range
> >> * @vcpu: Pointer to the VCPU struct
> >> *
> >> * Handle PSCI calls from guests through traps from HVC instructions.
> >> - * The calling convention is similar to SMC calls to the secure world where
> >> - * the function number is placed in r0 and this function returns true if the
> >> - * function number specified in r0 is withing the PSCI range, and false
> >> - * otherwise.
> >> + * The calling convention is similar to SMC calls to the secure world
> >> + * where the function number is placed in r0 and function number
> >
> > the function number
> >
> >> + * specified in r0 is withing the PSCI range.
> >
> > this reads a little funny now. I think you can get rid of everything
> > after the first mention of r0 (cut from "and function number...") since
> > you explain that in the error codes below.
>
> Sure, I will update this comment.
>
> >
> >> + *
> >> + * This function returns: > 0 (success), 0 (success but exit to user
> >> + * space), and < 0 (errors)
> >
> > you could use @return: instead of "This function returns", but I'm not
> > sure if anyone actually cares.
>
> Actually, "@returns" is correct way to specify as-per doxygen
> comment style for C but I have seen "Returns:" or "Returns" being
> used commonly in other parts of kernel. I will replace "The function
> returns:" with "Returns:".
>
Yes, but it doesn't seem that's what the kernel preferred style is
following:
$ grep -sInR '@return' * | wc -l
583
$ grep -sInR '@returns' * | wc -l
82
$ grep -sInR '@Returns' * | wc -l
1
$ grep -sInR '@Return' * | wc -l
1
Anyway, it's not a big deal in any case.
[...]
-Christoffer
^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2013-12-14 19:28 UTC | newest]
Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-12-12 16:12 [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Anup Patel
2013-12-12 16:12 ` [PATCH] arm64: KVM: Force undefined exception for Guest SMC intructions Anup Patel
2013-12-13 17:36 ` Marc Zyngier
2013-12-13 19:16 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH] KVM: Documentation: Fix typo for KVM_ARM_VCPU_INIT ioctl Anup Patel
2013-12-13 19:18 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH v2 0/2] PSCI system off and reset for KVM ARM/ARM64 Anup Patel
2013-12-13 19:19 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH v2 1/2] KVM: Add KVM_EXIT_SYSTEM_EVENT to user space API header Anup Patel
2013-12-13 19:22 ` Christoffer Dall
2013-12-12 16:12 ` [PATCH v2 2/2] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space Anup Patel
2013-12-13 20:08 ` Christoffer Dall
2013-12-14 13:24 ` Anup Patel
2013-12-14 19:28 ` Christoffer Dall
2013-12-13 17:35 ` [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest Marc Zyngier
2013-12-13 19:17 ` Christoffer Dall
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