[PATCH 27/40] KVM: SVM: add support for Nested Paging

From: Joerg Roedel <joerg.roedel@xxxxxxx>

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@xxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
arch/x86/kvm/svm.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 67 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 9e29a13..8e9d4a5 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)

+/* enable NPT for AMD64 and X86 with PAE */
+#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
+static bool npt_enabled = true;
+#else
static bool npt_enabled = false;
+#endif
static int npt = 1;

module_param(npt, int, 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;
@@ -573,6 +578,22 @@ 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);
+ control->intercept_cr_write &= ~(INTERCEPT_CR0_MASK|
+ INTERCEPT_CR3_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)
@@ -807,6 +828,9 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
}
}
#endif
+ if (npt_enabled)
+ goto set;
+
if ((vcpu->arch.cr0 & X86_CR0_TS) && !(cr0 & X86_CR0_TS)) {
svm->vmcb->control.intercept_exceptions &= ~(1 << NM_VECTOR);
vcpu->fpu_active = 1;
@@ -814,18 +838,26 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)

vcpu->arch.cr0 = cr0;
cr0 |= X86_CR0_PG | X86_CR0_WP;
- cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
if (!vcpu->fpu_active) {
svm->vmcb->control.intercept_exceptions |= (1 << NM_VECTOR);
cr0 |= X86_CR0_TS;
}
+set:
+ /*
+ * 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);
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,
@@ -1313,14 +1345,34 @@ 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) {
+ svm_set_cr0(vcpu, svm->vmcb->save.cr0);
+ mmu_reload = 1;
+ }
+ vcpu->arch.cr0 = svm->vmcb->save.cr0;
+ vcpu->arch.cr3 = svm->vmcb->save.cr3;
+ if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
+ if (!load_pdptrs(vcpu, vcpu->arch.cr3)) {
+ kvm_inject_gp(vcpu, 0);
+ return 1;
+ }
+ }
+ if (mmu_reload) {
+ kvm_mmu_reset_context(vcpu);
+ kvm_mmu_load(vcpu);
+ }
+ }
+
kvm_reput_irq(svm);

if (svm->vmcb->control.exit_code == SVM_EXIT_ERR) {
@@ -1331,7 +1383,8 @@ 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,
@@ -1522,6 +1575,9 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
svm->host_dr6 = read_dr6();
svm->host_dr7 = read_dr7();
svm->vmcb->save.cr2 = vcpu->arch.cr2;
+ /* required for live migration with NPT */
+ if (npt_enabled)
+ svm->vmcb->save.cr3 = vcpu->arch.cr3;

if (svm->vmcb->save.dr7 & 0xff) {
write_dr7(0);
@@ -1665,6 +1721,12 @@ 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);

--
1.5.4.5

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