[PATCH 26/40] KVM: MMU: add TDP support to the KVM MMU

From: Joerg Roedel <joerg.roedel@xxxxxxx>

This patch contains the changes to the KVM MMU necessary for support of the
Nested Paging feature in AMD Barcelona and Phenom Processors.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++--
arch/x86/kvm/mmu.h | 6 ++++
2 files changed, 82 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 33cd7c9..f7541fe 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1097,6 +1097,7 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
int i;
gfn_t root_gfn;
struct kvm_mmu_page *sp;
+ int metaphysical = 0;

root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;

@@ -1105,14 +1106,20 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
hpa_t root = vcpu->arch.mmu.root_hpa;

ASSERT(!VALID_PAGE(root));
+ if (tdp_enabled)
+ metaphysical = 1;
sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
- PT64_ROOT_LEVEL, 0, ACC_ALL, NULL);
+ PT64_ROOT_LEVEL, metaphysical,
+ ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
vcpu->arch.mmu.root_hpa = root;
return;
}
#endif
+ metaphysical = !is_paging(vcpu);
+ if (tdp_enabled)
+ metaphysical = 1;
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];

@@ -1126,7 +1133,7 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
} else if (vcpu->arch.mmu.root_level == 0)
root_gfn = 0;
sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
- PT32_ROOT_LEVEL, !is_paging(vcpu),
+ PT32_ROOT_LEVEL, metaphysical,
ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
@@ -1160,6 +1167,36 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
error_code & PFERR_WRITE_MASK, gfn);
}

+static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
+ u32 error_code)
+{
+ struct page *page;
+ int r;
+
+ ASSERT(vcpu);
+ ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
+
+ r = mmu_topup_memory_caches(vcpu);
+ if (r)
+ return r;
+
+ down_read(&current->mm->mmap_sem);
+ page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
+ if (is_error_page(page)) {
+ kvm_release_page_clean(page);
+ up_read(&current->mm->mmap_sem);
+ return 1;
+ }
+ spin_lock(&vcpu->kvm->mmu_lock);
+ kvm_mmu_free_some_pages(vcpu);
+ r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
+ gpa >> PAGE_SHIFT, page, TDP_ROOT_LEVEL);
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ up_read(&current->mm->mmap_sem);
+
+ return r;
+}
+
static void nonpaging_free(struct kvm_vcpu *vcpu)
{
mmu_free_roots(vcpu);
@@ -1253,7 +1290,35 @@ static int paging32E_init_context(struct kvm_vcpu *vcpu)
return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
}

-static int init_kvm_mmu(struct kvm_vcpu *vcpu)
+static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
+{
+ struct kvm_mmu *context = &vcpu->arch.mmu;
+
+ context->new_cr3 = nonpaging_new_cr3;
+ context->page_fault = tdp_page_fault;
+ context->free = nonpaging_free;
+ context->prefetch_page = nonpaging_prefetch_page;
+ context->shadow_root_level = TDP_ROOT_LEVEL;
+ context->root_hpa = INVALID_PAGE;
+
+ if (!is_paging(vcpu)) {
+ context->gva_to_gpa = nonpaging_gva_to_gpa;
+ context->root_level = 0;
+ } else if (is_long_mode(vcpu)) {
+ context->gva_to_gpa = paging64_gva_to_gpa;
+ context->root_level = PT64_ROOT_LEVEL;
+ } else if (is_pae(vcpu)) {
+ context->gva_to_gpa = paging64_gva_to_gpa;
+ context->root_level = PT32E_ROOT_LEVEL;
+ } else {
+ context->gva_to_gpa = paging32_gva_to_gpa;
+ context->root_level = PT32_ROOT_LEVEL;
+ }
+
+ return 0;
+}
+
+static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
@@ -1268,6 +1333,14 @@ static int init_kvm_mmu(struct kvm_vcpu *vcpu)
return paging32_init_context(vcpu);
}

+static int init_kvm_mmu(struct kvm_vcpu *vcpu)
+{
+ if (tdp_enabled)
+ return init_kvm_tdp_mmu(vcpu);
+ else
+ return init_kvm_softmmu(vcpu);
+}
+
static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 1fce19e..e64e9f5 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -3,6 +3,12 @@

#include <linux/kvm_host.h>

+#ifdef CONFIG_X86_64
+#define TDP_ROOT_LEVEL PT64_ROOT_LEVEL
+#else
+#define TDP_ROOT_LEVEL PT32E_ROOT_LEVEL
+#endif
+
static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
{
if (unlikely(vcpu->kvm->arch.n_free_mmu_pages < KVM_MIN_FREE_MMU_PAGES))
--
1.5.4.5

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