From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Nathan Lynch <nathanl@linux.ibm.com>,
Gautham R Shenoy <ego@linux.vnet.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
Waiman Long <longman@redhat.com>, Phil Auld <pauld@redhat.com>
Subject: [PATCH v2 3/4] powerpc: Reintroduce is_kvm_guest in a new avatar
Date: Wed, 2 Dec 2020 10:34:55 +0530 [thread overview]
Message-ID: <20201202050456.164005-4-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <20201202050456.164005-1-srikar@linux.vnet.ibm.com>
Introduce a static branch that would be set during boot if the OS
happens to be a KVM guest. Subsequent checks to see if we are on KVM
will rely on this static branch. This static branch would be used in
vcpu_is_preempted in a subsequent patch.
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Phil Auld <pauld@redhat.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/kvm_guest.h | 10 ++++++++++
arch/powerpc/include/asm/kvm_para.h | 2 +-
arch/powerpc/kernel/firmware.c | 2 ++
3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/kvm_guest.h b/arch/powerpc/include/asm/kvm_guest.h
index ba8291e02ba9..627ba272e781 100644
--- a/arch/powerpc/include/asm/kvm_guest.h
+++ b/arch/powerpc/include/asm/kvm_guest.h
@@ -7,8 +7,18 @@
#define __POWERPC_KVM_GUEST_H__
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST)
+#include <linux/jump_label.h>
+
+DECLARE_STATIC_KEY_FALSE(kvm_guest);
+
+static inline bool is_kvm_guest(void)
+{
+ return static_branch_unlikely(&kvm_guest);
+}
+
bool check_kvm_guest(void);
#else
+static inline bool is_kvm_guest(void) { return false; }
static inline bool check_kvm_guest(void) { return false; }
#endif
diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h
index 6fba06b6cfdb..abe1b5e82547 100644
--- a/arch/powerpc/include/asm/kvm_para.h
+++ b/arch/powerpc/include/asm/kvm_para.h
@@ -14,7 +14,7 @@
static inline int kvm_para_available(void)
{
- return IS_ENABLED(CONFIG_KVM_GUEST) && check_kvm_guest();
+ return IS_ENABLED(CONFIG_KVM_GUEST) && is_kvm_guest();
}
static inline unsigned int kvm_arch_para_features(void)
diff --git a/arch/powerpc/kernel/firmware.c b/arch/powerpc/kernel/firmware.c
index 0aeb6a5b1a9e..28498fc573f2 100644
--- a/arch/powerpc/kernel/firmware.c
+++ b/arch/powerpc/kernel/firmware.c
@@ -22,6 +22,7 @@ EXPORT_SYMBOL_GPL(powerpc_firmware_features);
#endif
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST)
+DEFINE_STATIC_KEY_FALSE(kvm_guest);
bool check_kvm_guest(void)
{
struct device_node *hyper_node;
@@ -33,6 +34,7 @@ bool check_kvm_guest(void)
if (!of_device_is_compatible(hyper_node, "linux,kvm"))
return 0;
+ static_branch_enable(&kvm_guest);
return 1;
}
#endif
--
2.18.4
next prev parent reply other threads:[~2020-12-02 5:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 5:04 [PATCH v2 0/4] Powerpc: Better preemption for shared processor Srikar Dronamraju
2020-12-02 5:04 ` [PATCH v2 1/4] powerpc: Refactor is_kvm_guest declaration to new header Srikar Dronamraju
2020-12-02 5:04 ` [PATCH v2 2/4] powerpc: Rename is_kvm_guest to check_kvm_guest Srikar Dronamraju
2020-12-02 5:04 ` Srikar Dronamraju [this message]
2020-12-02 5:04 ` [PATCH v2 4/4] powerpc/paravirt: Use is_kvm_guest in vcpu_is_preempted Srikar Dronamraju
2020-12-10 11:30 ` [PATCH v2 0/4] Powerpc: Better preemption for shared processor Michael Ellerman
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