[patch 4/4] KVM: allow direct access to PMTimer port

[Marcelo Tosatti <mtosatti@redhat.com>]

[-- Attachment #1: kvm-open-pmtmr --]
[-- Type: text/plain, Size: 3581 bytes --]

There's not much point in exiting for pmtimer reads, since it runs at a
fixed clock rate and its start value is undefined.

The KVM-specific ioctl to read the counter from userspace is not nice
though. Ideas?

CC: Len Brown <lenb@kernel.org>


diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index baf9607..f7e44d8 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -24,6 +24,7 @@
 #include <linux/vmalloc.h>
 #include <linux/highmem.h>
 #include <linux/sched.h>
+#include <linux/acpi_pmtmr.h>
 
 #include <asm/desc.h>
 
@@ -424,6 +425,10 @@ static __init int svm_hardware_setup(void)
 	iopm_va = page_address(iopm_pages);
 	memset(iopm_va, 0xff, PAGE_SIZE * (1 << IOPM_ALLOC_ORDER));
 	clear_bit(0x80, iopm_va); /* allow direct access to PC debug port */
+	if (pmtmr_ioport)
+		for (r = 0; r < 4; r++)
+			clear_bit(pmtmr_ioport+r, iopm_va);
+            
 	iopm_base = page_to_pfn(iopm_pages) << PAGE_SHIFT;
 
 	if (boot_cpu_has(X86_FEATURE_NX))
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index aaa99ed..4f77fd7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -26,6 +26,7 @@
 #include <linux/highmem.h>
 #include <linux/sched.h>
 #include <linux/moduleparam.h>
+#include <linux/acpi_pmtmr.h>
 
 #include <asm/io.h>
 #include <asm/desc.h>
@@ -3261,6 +3262,10 @@ static int __init vmx_init(void)
 	va = kmap(vmx_io_bitmap_a);
 	memset(va, 0xff, PAGE_SIZE);
 	clear_bit(0x80, va);
+	if (pmtmr_ioport)
+		for (r = 0; r < 4; r++)
+			clear_bit(pmtmr_ioport+r, va);
+
 	kunmap(vmx_io_bitmap_a);
 
 	va = kmap(vmx_io_bitmap_b);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e537005..9769f52 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -27,6 +27,7 @@
 #include <linux/module.h>
 #include <linux/mman.h>
 #include <linux/highmem.h>
+#include <linux/acpi_pmtmr.h>
 
 #include <asm/uaccess.h>
 #include <asm/msr.h>
@@ -790,6 +791,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_PIT:
 	case KVM_CAP_NOP_IO_DELAY:
 	case KVM_CAP_MP_STATE:
+	case KVM_CAP_GET_PMTIMER:
 		r = 1;
 		break;
 	case KVM_CAP_VAPIC:
@@ -1678,6 +1680,18 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = 0;
 		break;
 	}
+	case KVM_GET_PMTIMER: {
+		struct kvm_pmtimer pmtmr;
+		r = -ENODEV;
+		if (!pmtmr_ioport)
+			goto out;
+		pmtmr.val = inl(pmtmr_ioport);
+		r = -EFAULT;
+		if (copy_to_user(argp, &pmtmr, sizeof pmtmr))
+			goto out;
+		r = 0;
+		break;
+	}
 	default:
 		;
 	}
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
index 7b46faf..d3d4294 100644
--- a/drivers/clocksource/acpi_pm.c
+++ b/drivers/clocksource/acpi_pm.c
@@ -29,6 +29,7 @@
  * in arch/i386/kernel/acpi/boot.c
  */
 u32 pmtmr_ioport __read_mostly;
+EXPORT_SYMBOL(pmtmr_ioport);
 
 static inline u32 read_pmtmr(void)
 {
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index a281afe..3672890 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -247,6 +247,10 @@ struct kvm_mp_state {
 	__u32 mp_state;
 };
 
+struct kvm_pmtimer {
+	__u32 val;
+};
+
 struct kvm_s390_psw {
 	__u64 mask;
 	__u64 addr;
@@ -346,6 +350,7 @@ struct kvm_trace_rec {
 #define KVM_CAP_NOP_IO_DELAY 12
 #define KVM_CAP_PV_MMU 13
 #define KVM_CAP_MP_STATE 14
+#define KVM_CAP_GET_PMTIMER 15
 
 /*
  * ioctls for VM fds
@@ -371,6 +376,7 @@ struct kvm_trace_rec {
 #define KVM_CREATE_PIT		  _IO(KVMIO,  0x64)
 #define KVM_GET_PIT		  _IOWR(KVMIO, 0x65, struct kvm_pit_state)
 #define KVM_SET_PIT		  _IOR(KVMIO,  0x66, struct kvm_pit_state)
+#define KVM_GET_PMTIMER 	  _IOR(KVMIO,  0x67, struct kvm_pmtimer)
 
 /*
  * ioctls for vcpu fds

--