[PATCH 7/7] kvm x86: report 1GB page support to userspace

Joerg Roedel
2009-03-27T14:33:59Z

If userspace knows that the kernel part supports 1GB pages it can enable
the corresponding cpuid bit so that guests actually use GB pages.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/svm.c | 7 +++++++
arch/x86/kvm/vmx.c | 7 +++++++
arch/x86/kvm/x86.c | 6 +++++-
include/linux/kvm.h | 1 +
5 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a1df2a3..6593198 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -542,6 +542,8 @@ struct kvm_x86_ops {
int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
int (*get_tdp_level)(void);
int (*get_mt_mask_shift)(void);
+
+ bool (*gb_page_enable)(void);
};

extern struct kvm_x86_ops *kvm_x86_ops;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1fcbc17..d140686 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2604,6 +2604,11 @@ static int svm_get_mt_mask_shift(void)
return 0;
}

+static bool svm_gb_page_enable(void)
+{
+ return npt_enabled;
+}
+
static struct kvm_x86_ops svm_x86_ops = {
.cpu_has_kvm_support = has_svm,
.disabled_by_bios = is_disabled,
@@ -2661,6 +2666,8 @@ static struct kvm_x86_ops svm_x86_ops = {
.set_tss_addr = svm_set_tss_addr,
.get_tdp_level = get_npt_level,
.get_mt_mask_shift = svm_get_mt_mask_shift,
+
+ .gb_page_enable = svm_gb_page_enable,
};

static int __init svm_init(void)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 37ae13d..e54af3f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3647,6 +3647,11 @@ static int vmx_get_mt_mask_shift(void)
return VMX_EPT_MT_EPTE_SHIFT;
}

+static bool vmx_gb_page_enable(void)
+{
+ return false;
+}
+
static struct kvm_x86_ops vmx_x86_ops = {
.cpu_has_kvm_support = cpu_has_kvm_support,
.disabled_by_bios = vmx_disabled_by_bios,
@@ -3702,6 +3707,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
.set_tss_addr = vmx_set_tss_addr,
.get_tdp_level = get_ept_level,
.get_mt_mask_shift = vmx_get_mt_mask_shift,
+
+ .gb_page_enable = vmx_gb_page_enable,
};

static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ae4918c..c94f231 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1009,7 +1009,7 @@ out:

int kvm_dev_ioctl_check_extension(long ext)
{
- int r;
+ int r = 0;

switch (ext) {
case KVM_CAP_IRQCHIP:
@@ -1027,6 +1027,10 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_ASSIGN_DEV_IRQ:
r = 1;
break;
+ case KVM_CAP_1GB_PAGES:
+ if (kvm_x86_ops->gb_page_enable())
+ r = 1;
+ break;
case KVM_CAP_COALESCED_MMIO:
r = KVM_COALESCED_MMIO_PAGE_OFFSET;
break;
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index ee755e2..e79eb26 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -413,6 +413,7 @@ struct kvm_trace_rec {
#define KVM_CAP_DEVICE_MSIX 28
#endif
#define KVM_CAP_ASSIGN_DEV_IRQ 29
+#define KVM_CAP_1GB_PAGES 30

#ifdef KVM_CAP_IRQ_ROUTING

--
1.5.6.4