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Commit 3e7c73e9 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: VMX: Don't use highmem pages for the msr and pio bitmaps 



Highmem pages are a pain, and saving three lowmem pages on i386 isn't worth
the extra code.

Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 07a2039b

arch/x86/kvm/vmx.c

+25 −34
Original line number Diff line number Diff line
@@ -111,9 +111,9 @@ static DEFINE_PER_CPU(struct vmcs *, vmxarea); 
static DEFINE_PER_CPU(struct vmcs *, current_vmcs);

static DEFINE_PER_CPU(struct list_head, vcpus_on_cpu);



static struct page *vmx_io_bitmap_a;

static struct page *vmx_io_bitmap_b;

static struct page *vmx_msr_bitmap;

static unsigned long *vmx_io_bitmap_a;

static unsigned long *vmx_io_bitmap_b;

static unsigned long *vmx_msr_bitmap;



static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS);

static DEFINE_SPINLOCK(vmx_vpid_lock);
@@ -2082,9 +2082,9 @@ static void allocate_vpid(struct vcpu_vmx *vmx) 
	spin_unlock(&vmx_vpid_lock);

}



static void vmx_disable_intercept_for_msr(struct page *msr_bitmap, u32 msr)

static void vmx_disable_intercept_for_msr(unsigned long *msr_bitmap, u32 msr)

{

	void *va;

	int f = sizeof(unsigned long);



	if (!cpu_has_vmx_msr_bitmap())

		return;
@@ -2094,16 +2094,14 @@ static void vmx_disable_intercept_for_msr(struct page *msr_bitmap, u32 msr) 
	 * have the write-low and read-high bitmap offsets the wrong way round.

	 * We can control MSRs 0x00000000-0x00001fff and 0xc0000000-0xc0001fff.

	 */

	va = kmap(msr_bitmap);

	if (msr <= 0x1fff) {

		__clear_bit(msr, va + 0x000); /* read-low */

		__clear_bit(msr, va + 0x800); /* write-low */

		__clear_bit(msr, msr_bitmap + 0x000 / f); /* read-low */

		__clear_bit(msr, msr_bitmap + 0x800 / f); /* write-low */

	} else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {

		msr &= 0x1fff;

		__clear_bit(msr, va + 0x400); /* read-high */

		__clear_bit(msr, va + 0xc00); /* write-high */

		__clear_bit(msr, msr_bitmap + 0x400 / f); /* read-high */

		__clear_bit(msr, msr_bitmap + 0xc00 / f); /* write-high */

	}

	kunmap(msr_bitmap);

}



/*
@@ -2121,11 +2119,11 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) 
	u32 exec_control;



	/* I/O */

	vmcs_write64(IO_BITMAP_A, page_to_phys(vmx_io_bitmap_a));

	vmcs_write64(IO_BITMAP_B, page_to_phys(vmx_io_bitmap_b));

	vmcs_write64(IO_BITMAP_A, __pa(vmx_io_bitmap_a));

	vmcs_write64(IO_BITMAP_B, __pa(vmx_io_bitmap_b));



	if (cpu_has_vmx_msr_bitmap())

		vmcs_write64(MSR_BITMAP, page_to_phys(vmx_msr_bitmap));

		vmcs_write64(MSR_BITMAP, __pa(vmx_msr_bitmap));



	vmcs_write64(VMCS_LINK_POINTER, -1ull); /* 22.3.1.5 */
@@ -3695,20 +3693,19 @@ static struct kvm_x86_ops vmx_x86_ops = { 


static int __init vmx_init(void)

{

	void *va;

	int r;



	vmx_io_bitmap_a = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);

	vmx_io_bitmap_a = (unsigned long *)__get_free_page(GFP_KERNEL);

	if (!vmx_io_bitmap_a)

		return -ENOMEM;



	vmx_io_bitmap_b = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);

	vmx_io_bitmap_b = (unsigned long *)__get_free_page(GFP_KERNEL);

	if (!vmx_io_bitmap_b) {

		r = -ENOMEM;

		goto out;

	}



	vmx_msr_bitmap = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);

	vmx_msr_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);

	if (!vmx_msr_bitmap) {

		r = -ENOMEM;

		goto out1;
@@ -3718,18 +3715,12 @@ static int __init vmx_init(void) 
	 * Allow direct access to the PC debug port (it is often used for I/O

	 * delays, but the vmexits simply slow things down).

	 */

	va = kmap(vmx_io_bitmap_a);

	memset(va, 0xff, PAGE_SIZE);

	clear_bit(0x80, va);

	kunmap(vmx_io_bitmap_a);

	memset(vmx_io_bitmap_a, 0xff, PAGE_SIZE);

	clear_bit(0x80, vmx_io_bitmap_a);



	va = kmap(vmx_io_bitmap_b);

	memset(va, 0xff, PAGE_SIZE);

	kunmap(vmx_io_bitmap_b);

	memset(vmx_io_bitmap_b, 0xff, PAGE_SIZE);



	va = kmap(vmx_msr_bitmap);

	memset(va, 0xff, PAGE_SIZE);

	kunmap(vmx_msr_bitmap);

	memset(vmx_msr_bitmap, 0xff, PAGE_SIZE);



	set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
@@ -3762,19 +3753,19 @@ static int __init vmx_init(void) 
	return 0;



out2:

	__free_page(vmx_msr_bitmap);

	free_page((unsigned long)vmx_msr_bitmap);

out1:

	__free_page(vmx_io_bitmap_b);

	free_page((unsigned long)vmx_io_bitmap_b);

out:

	__free_page(vmx_io_bitmap_a);

	free_page((unsigned long)vmx_io_bitmap_a);

	return r;

}



static void __exit vmx_exit(void)

{

	__free_page(vmx_msr_bitmap);

	__free_page(vmx_io_bitmap_b);

	__free_page(vmx_io_bitmap_a);

	free_page((unsigned long)vmx_msr_bitmap);

	free_page((unsigned long)vmx_io_bitmap_b);

	free_page((unsigned long)vmx_io_bitmap_a);



	kvm_exit();

}