On 23/10/2019 13:39, Marc Zyngier wrote:
> Hi Steven,
>
> On 2019-10-21 16:28, Steven Price wrote:
>> This series add support for paravirtualized time for arm64 guests and
>> KVM hosts following the specification in Arm's document DEN 0057A:
>>
>> https://developer.arm.com/docs/den0057/a
>>
>> It implements support for stolen time, allowing the guest to
>> identify time when it is forcibly not executing.
>>
>> Note that Live Physical Time (LPT) which was previously part of the
>> above specification has now been removed.
>>
>> Also available as a git tree:
>> git://linux-arm.org/linux-sp.git stolen_time/v7
>
> Can you please point me to userspace patches that I could apply to
> kvmtool? I'd like to give this series a go as part of my normal testing.
I don't have a proper patch yet, but the below is what I've been testing
with (this breaks with kernels without PV-time).
Steve
----8<----
>From 8f6540cfbe2842f3ee422c07fbd1f590534cc90a Mon Sep 17 00:00:00 2001
From: Steven Price <steven.pr...@arm.com>
Date: Thu, 8 Nov 2018 13:43:56 +0000
Subject: [PATCH kvmtool] ARM PV time support
Signed-off-by: Steven Price <steven.pr...@arm.com>
---
Makefile | 2 +-
arm/kvm-cpu.c | 4 ++++
arm/pvtime.c | 47 ++++++++++++++++++++++++++++++++++++++++
include/kvm/arm-pvtime.h | 6 +++++
4 files changed, 58 insertions(+), 1 deletion(-)
create mode 100644 arm/pvtime.c
create mode 100644 include/kvm/arm-pvtime.h
diff --git a/Makefile b/Makefile
index 3862112..a79956b 100644
--- a/Makefile
+++ b/Makefile
@@ -158,7 +158,7 @@ endif
# ARM
OBJS_ARM_COMMON := arm/fdt.o arm/gic.o arm/gicv2m.o
arm/ioport.o \
arm/kvm.o arm/kvm-cpu.o arm/pci.o arm/timer.o \
- arm/pmu.o
+ arm/pmu.o arm/pvtime.o
HDRS_ARM_COMMON := arm/include
ifeq ($(ARCH), arm)
DEFINES += -DCONFIG_ARM
diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 7780251..c903b05 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -1,5 +1,6 @@
#include "kvm/kvm.h"
#include "kvm/kvm-cpu.h"
+#include "kvm/arm-pvtime.h"
static int debug_fd;
@@ -122,6 +123,9 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm,
unsigned long cpu_id)
vcpu->cpu_compatible = target->compatible;
vcpu->is_running = true;
+ if (pvtime_vcpu_init(vcpu))
+ die("Unable to initialise pvtime");
+
return vcpu;
}
diff --git a/arm/pvtime.c b/arm/pvtime.c
new file mode 100644
index 0000000..fc152d3
--- /dev/null
+++ b/arm/pvtime.c
@@ -0,0 +1,47 @@
+#include "kvm/kvm.h"
+#include "kvm/kvm-cpu.h"
+#include "kvm/arm-pvtime.h"
+
+#define PVTIME_BASE 0x10000000
+
+#define KVM_ARM_VCPU_PVTIME_CTRL 2
+#define KVM_ARM_VCPU_PVTIME_IPA 0
+
+static int pvtime_init(struct kvm *kvm)
+{
+ char *mem;
+ int size = ALIGN(64 * kvm->cfg.nrcpus, PAGE_SIZE);
+
+ mem = mmap(NULL, size, PROT_RW, MAP_ANON_NORESERVE, -1, 0);
+ if (mem == MAP_FAILED)
+ return -ENOMEM;
+
+ if (kvm__register_dev_mem(kvm, PVTIME_BASE, size, mem))
+ return -EINVAL;
+
+ return 0;
+}
+
+base_init(pvtime_init);
+
+int pvtime_vcpu_init(struct kvm_cpu *vcpu)
+{
+ int err;
+ u64 st_paddr = PVTIME_BASE;
+
+ st_paddr += vcpu->cpu_id * 64;
+
+ struct kvm_device_attr st_base = {
+ .group = KVM_ARM_VCPU_PVTIME_CTRL,
+ .attr = KVM_ARM_VCPU_PVTIME_IPA,
+ .addr = (u64)&st_paddr
+ };
+
+ err = ioctl(vcpu->vcpu_fd, KVM_SET_DEVICE_ATTR, &st_base);
+ if (err) {
+ perror("ioctl st_base failed");
+ return err;
+ }
+
+ return 0;
+}
diff --git a/include/kvm/arm-pvtime.h b/include/kvm/arm-pvtime.h
new file mode 100644
index 0000000..f5db286
--- /dev/null
+++ b/include/kvm/arm-pvtime.h
@@ -0,0 +1,6 @@
+#ifndef ARM_PVTIME_H
+#define ARM_PVTIME_H
+
+int pvtime_vcpu_init(struct kvm_cpu *vcpu);
+
+#endif
--
2.20.1
