[PATCH 8/8] SVM: add support for Nested Paging

Joerg Roedel
2008-01-25T20:56:07Z

This patch contains the SVM architecture dependent changes for KVM to enable
support for the Nested Paging feature of AMD Barcelona and Phenom processors.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/x86/kvm/svm.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d0bfdd8..578d8ec 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -47,7 +47,12 @@ MODULE_LICENSE("GPL");
#define SVM_FEATURE_LBRV (1 << 1)
#define SVM_DEATURE_SVML (1 << 2)

+#ifdef CONFIG_X86_64
+static bool npt_enabled = true;
+#else
static bool npt_enabled = false;
+#endif
+
static char *npt = "on";

module_param(npt, charp, S_IRUGO);
@@ -187,7 +192,7 @@ static inline void flush_guest_tlb(struct kvm_vcpu *vcpu)

static void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
- if (!(efer & EFER_LMA))
+ if (!npt_enabled && !(efer & EFER_LMA))
efer &= ~EFER_LME;

to_svm(vcpu)->vmcb->save.efer = efer | MSR_EFER_SVME_MASK;
@@ -568,6 +573,24 @@ static void init_vmcb(struct vmcb *vmcb)
save->cr0 = 0x00000010 | X86_CR0_PG | X86_CR0_WP;
save->cr4 = X86_CR4_PAE;
/* rdx = ?? */
+
+ if (npt_enabled) {
+ /* Setup VMCB for Nested Paging */
+ control->nested_ctl = 1;
+ control->intercept_exceptions &= ~(1 << PF_VECTOR);
+ control->intercept_cr_read &= ~(INTERCEPT_CR0_MASK|
+ INTERCEPT_CR3_MASK|
+ INTERCEPT_CR4_MASK);
+ control->intercept_cr_write &= ~(INTERCEPT_CR0_MASK|
+ INTERCEPT_CR3_MASK|
+ INTERCEPT_CR4_MASK);
+ save->g_pat = 0x0007040600070406ULL;
+ /* enable caching because the QEMU Bios doesn't enable it */
+ save->cr0 = X86_CR0_ET;
+ save->cr3 = 0;
+ save->cr4 = 0;
+ }
+
}

static int svm_vcpu_reset(struct kvm_vcpu *vcpu)
@@ -789,6 +812,15 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
struct vcpu_svm *svm = to_svm(vcpu);

+ if (npt_enabled) {
+ /*
+ * re-enable caching here because the QEMU bios
+ * does not do it - this results in some delay at
+ * reboot
+ */
+ cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
+ goto set;
+ }
#ifdef CONFIG_X86_64
if (vcpu->arch.shadow_efer & EFER_LME) {
if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
@@ -812,13 +844,16 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
if (!vcpu->fpu_active)
cr0 |= X86_CR0_TS;
+set:
svm->vmcb->save.cr0 = cr0;
}

static void svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
vcpu->arch.cr4 = cr4;
- to_svm(vcpu)->vmcb->save.cr4 = cr4 | X86_CR4_PAE;
+ if (!npt_enabled)
+ cr4 |= X86_CR4_PAE;
+ to_svm(vcpu)->vmcb->save.cr4 = cr4;
}

static void svm_set_segment(struct kvm_vcpu *vcpu,
@@ -1284,14 +1319,31 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm,
[SVM_EXIT_WBINVD] = emulate_on_interception,
[SVM_EXIT_MONITOR] = invalid_op_interception,
[SVM_EXIT_MWAIT] = invalid_op_interception,
+ [SVM_EXIT_NPF] = pf_interception,
};

-
static int handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
u32 exit_code = svm->vmcb->control.exit_code;

+ if (npt_enabled) {
+ int mmu_reload = 0;
+ if (((vcpu->arch.cr0 ^ svm->vmcb->save.cr0) & X86_CR0_PG)
+ || ((vcpu->arch.cr4 ^ svm->vmcb->save.cr4) &
+ (X86_CR4_PGE|X86_CR4_PAE)))
+ mmu_reload = 1;
+ vcpu->arch.cr0 = svm->vmcb->save.cr0;
+ vcpu->arch.cr4 = svm->vmcb->save.cr4;
+ vcpu->arch.cr3 = svm->vmcb->save.cr3;
+ if (mmu_reload) {
+ kvm_mmu_reset_context(vcpu);
+ kvm_mmu_load(vcpu);
+ }
+ if (is_pae(vcpu) && !is_long_mode(vcpu))
+ load_pdptrs(vcpu, vcpu->arch.cr3);
+ }
+
kvm_reput_irq(svm);

if (svm->vmcb->control.exit_code == SVM_EXIT_ERR) {
@@ -1302,7 +1354,8 @@ static int handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
}

if (is_external_interrupt(svm->vmcb->control.exit_int_info) &&
- exit_code != SVM_EXIT_EXCP_BASE + PF_VECTOR)
+ exit_code != SVM_EXIT_EXCP_BASE + PF_VECTOR &&
+ exit_code != SVM_EXIT_NPF)
printk(KERN_ERR "%s: unexpected exit_ini_info 0x%x "
"exit_code 0x%x\n",
__FUNCTION__, svm->vmcb->control.exit_int_info,
@@ -1636,6 +1689,12 @@ static void svm_set_cr3(struct kvm_vcpu *vcpu, unsigned long root)
{
struct vcpu_svm *svm = to_svm(vcpu);

+ if (npt_enabled) {
+ svm->vmcb->control.nested_cr3 = root;
+ force_new_asid(vcpu);
+ return;
+ }
+
svm->vmcb->save.cr3 = root;
force_new_asid(vcpu);

--
1.5.3.7