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Message-Id: <20180126142847.31240-9-marc.zyngier@arm.com>
Date: Fri, 26 Jan 2018 14:28:41 +0000
From: Marc Zyngier <marc.zyngier@....com>
To: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.cs.columbia.edu
Cc: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Peter Maydell <peter.maydell@...aro.org>,
Christoffer Dall <christoffer.dall@...aro.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Mark Rutland <mark.rutland@....com>,
Jon Masters <jcm@...hat.com>
Subject: [PATCH 08/14] arm/arm64: KVM: Advertise SMCCC v1.1
The new SMC Calling Convention (v1.1) allows for a reduced overhead
when calling into the firmware, and provides a new feature discovery
mechanism.
Make it visible to KVM guests.
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
Documentation/virtual/kvm/arm/psci.txt | 12 +++++++-----
arch/arm/kvm/handle_exit.c | 2 +-
arch/arm64/kvm/handle_exit.c | 2 +-
include/kvm/arm_psci.h | 2 +-
include/linux/arm-smccc.h | 13 +++++++++++++
virt/kvm/arm/psci.c | 24 +++++++++++++++++++++++-
6 files changed, 46 insertions(+), 9 deletions(-)
diff --git a/Documentation/virtual/kvm/arm/psci.txt b/Documentation/virtual/kvm/arm/psci.txt
index 2e49a4e9f084..aafdab887b04 100644
--- a/Documentation/virtual/kvm/arm/psci.txt
+++ b/Documentation/virtual/kvm/arm/psci.txt
@@ -13,7 +13,7 @@ a migration causes a different PSCI version to be exposed out of the
blue to an unsuspecting guest.
In order to remedy this situation, KVM exposes a set of "firmware
-pseuodo-registers" that can be manipulated using the GET/SET_ONE_REG
+pseudo-registers" that can be manipulated using the GET/SET_ONE_REG
interface. These registers can be saved/restored by userspace, and set
to a convenient value if required.
@@ -21,8 +21,10 @@ The following register is defined:
* KVM_REG_ARM_PSCI_VERSION:
- - Only valid if the vcpu has KVM_ARM_VCPU_PSCI_0_2 feature set
- - Returns the current PSCI version on GET_ONE_REG
- - Allows any supported PSCI version compatible with v0.2 to be set
- with SET_ONE_REG
+ - Only valid if the vcpu has the KVM_ARM_VCPU_PSCI_0_2 feature set
+ (and thus has already been initialized)
+ - Returns the current PSCI version on GET_ONE_REG (defaulting to the
+ highest PSCI version implemented by KVM and compatible with v0.2)
+ - Allows any PSCI version implemented by KVM and compatible with
+ v0.2 to be set with SET_ONE_REG
- Affects the whole VM (even if the register view is per-vcpu)
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index e020cc82c4b1..a4520c7118d2 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -36,7 +36,7 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
kvm_vcpu_hvc_get_imm(vcpu));
vcpu->stat.hvc_exit_stat++;
- ret = kvm_psci_call(vcpu);
+ ret = kvm_hvc_call_handler(vcpu);
if (ret < 0) {
vcpu_set_reg(vcpu, 0, ~0UL);
return 1;
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 97e8d64a203d..bb6e1518d819 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -52,7 +52,7 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
kvm_vcpu_hvc_get_imm(vcpu));
vcpu->stat.hvc_exit_stat++;
- ret = kvm_psci_call(vcpu);
+ ret = kvm_hvc_call_handler(vcpu);
if (ret < 0) {
vcpu_set_reg(vcpu, 0, ~0UL);
return 1;
diff --git a/include/kvm/arm_psci.h b/include/kvm/arm_psci.h
index f2fa7d752c4e..4876bfac2195 100644
--- a/include/kvm/arm_psci.h
+++ b/include/kvm/arm_psci.h
@@ -26,7 +26,7 @@
#define KVM_ARM_PSCI_LATEST KVM_ARM_PSCI_1_0
int kvm_psci_version(struct kvm_vcpu *vcpu);
-int kvm_psci_call(struct kvm_vcpu *vcpu);
+int kvm_hvc_call_handler(struct kvm_vcpu *vcpu);
struct kvm_one_reg;
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 4c5bca38c653..dc68aa5a7261 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -60,6 +60,19 @@
#define ARM_SMCCC_QUIRK_NONE 0
#define ARM_SMCCC_QUIRK_QCOM_A6 1 /* Save/restore register a6 */
+#define ARM_SMCCC_VERSION_1_0 0x10000
+#define ARM_SMCCC_VERSION_1_1 0x10001
+
+#define ARM_SMCCC_VERSION_FUNC_ID \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
+ ARM_SMCCC_SMC_32, \
+ 0, 0)
+
+#define ARM_SMCCC_ARCH_FEATURES_FUNC_ID \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
+ ARM_SMCCC_SMC_32, \
+ 0, 1)
+
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index 682f9be6264b..3bb336ac7d7d 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -15,6 +15,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <linux/arm-smccc.h>
#include <linux/preempt.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
@@ -353,6 +354,7 @@ static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu)
case PSCI_0_2_FN_SYSTEM_OFF:
case PSCI_0_2_FN_SYSTEM_RESET:
case PSCI_1_0_FN_PSCI_FEATURES:
+ case ARM_SMCCC_VERSION_FUNC_ID:
val = 0;
break;
default:
@@ -407,7 +409,7 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
* Errors:
* -EINVAL: Unrecognized PSCI function
*/
-int kvm_psci_call(struct kvm_vcpu *vcpu)
+static int kvm_psci_call(struct kvm_vcpu *vcpu)
{
switch (kvm_psci_version(vcpu)) {
case KVM_ARM_PSCI_1_0:
@@ -421,6 +423,26 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)
};
}
+int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
+{
+ u32 func_id = smccc_get_function(vcpu);
+ u32 val;
+
+ switch (func_id) {
+ case ARM_SMCCC_VERSION_FUNC_ID:
+ val = ARM_SMCCC_VERSION_1_1;
+ break;
+ case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
+ val = -1; /* Nothing supported yet */
+ break;
+ default:
+ return kvm_psci_call(vcpu);
+ }
+
+ smccc_set_retval(vcpu, val, 0, 0, 0);
+ return 1;
+}
+
int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
{
return 1; /* PSCI version */
--
2.14.2
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