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

[Avi Kivity]

Marcelo Tosatti wrote:

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 <[EMAIL PROTECTED]>


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);

+

What if the port conflicts with a virtualized port?

        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);
+

Instead of duplicating the code, how about an kvm_x86_ops interface?

        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:

This definitely doesn't belong in kvm.  /dev/pmtimer?



--
error compiling committee.c: too many arguments to function

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