lkml.org 
[lkml]   [2020]   [Apr]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] KVM: x86/mmu: Add a helper to consolidate root sp allocation
Date
Add a helper, mmu_alloc_root(), to consolidate the allocation of a root
shadow page, which has the same basic mechanics for all flavors of TDP
and shadow paging.

Note, __pa(sp->spt) doesn't need to be protected by mmu_lock, sp->spt
points at a kernel page.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 88 +++++++++++++++++++-----------------------
1 file changed, 39 insertions(+), 49 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e618472c572b..80205aea296e 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3685,37 +3685,43 @@ static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
return ret;
}

+static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gva,
+ u8 level, bool direct)
+{
+ struct kvm_mmu_page *sp;
+
+ spin_lock(&vcpu->kvm->mmu_lock);
+
+ if (make_mmu_pages_available(vcpu)) {
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ return INVALID_PAGE;
+ }
+ sp = kvm_mmu_get_page(vcpu, gfn, gva, level, direct, ACC_ALL);
+ ++sp->root_count;
+
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ return __pa(sp->spt);
+}
+
static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
{
- struct kvm_mmu_page *sp;
+ u8 shadow_root_level = vcpu->arch.mmu->shadow_root_level;
+ hpa_t root;
unsigned i;

- if (vcpu->arch.mmu->shadow_root_level >= PT64_ROOT_4LEVEL) {
- spin_lock(&vcpu->kvm->mmu_lock);
- if(make_mmu_pages_available(vcpu) < 0) {
- spin_unlock(&vcpu->kvm->mmu_lock);
+ if (shadow_root_level >= PT64_ROOT_4LEVEL) {
+ root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level, true);
+ if (!VALID_PAGE(root))
return -ENOSPC;
- }
- sp = kvm_mmu_get_page(vcpu, 0, 0,
- vcpu->arch.mmu->shadow_root_level, 1, ACC_ALL);
- ++sp->root_count;
- spin_unlock(&vcpu->kvm->mmu_lock);
- vcpu->arch.mmu->root_hpa = __pa(sp->spt);
- } else if (vcpu->arch.mmu->shadow_root_level == PT32E_ROOT_LEVEL) {
+ vcpu->arch.mmu->root_hpa = root;
+ } else if (shadow_root_level == PT32E_ROOT_LEVEL) {
for (i = 0; i < 4; ++i) {
- hpa_t root = vcpu->arch.mmu->pae_root[i];
+ MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->pae_root[i]));

- MMU_WARN_ON(VALID_PAGE(root));
- spin_lock(&vcpu->kvm->mmu_lock);
- if (make_mmu_pages_available(vcpu) < 0) {
- spin_unlock(&vcpu->kvm->mmu_lock);
+ root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT),
+ i << 30, PT32_ROOT_LEVEL, true);
+ if (!VALID_PAGE(root))
return -ENOSPC;
- }
- sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
- i << 30, PT32_ROOT_LEVEL, 1, ACC_ALL);
- root = __pa(sp->spt);
- ++sp->root_count;
- spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu->pae_root[i] = root | PT_PRESENT_MASK;
}
vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root);
@@ -3730,9 +3736,9 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)

static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
{
- struct kvm_mmu_page *sp;
u64 pdptr, pm_mask;
gfn_t root_gfn, root_pgd;
+ hpa_t root;
int i;

root_pgd = vcpu->arch.mmu->get_guest_pgd(vcpu);
@@ -3746,20 +3752,12 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
* write-protect the guests page table root.
*/
if (vcpu->arch.mmu->root_level >= PT64_ROOT_4LEVEL) {
- hpa_t root = vcpu->arch.mmu->root_hpa;
+ MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->root_hpa));

- MMU_WARN_ON(VALID_PAGE(root));
-
- spin_lock(&vcpu->kvm->mmu_lock);
- if (make_mmu_pages_available(vcpu) < 0) {
- spin_unlock(&vcpu->kvm->mmu_lock);
+ root = mmu_alloc_root(vcpu, root_gfn, 0,
+ vcpu->arch.mmu->shadow_root_level, false);
+ if (!VALID_PAGE(root))
return -ENOSPC;
- }
- sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
- vcpu->arch.mmu->shadow_root_level, 0, ACC_ALL);
- root = __pa(sp->spt);
- ++sp->root_count;
- spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu->root_hpa = root;
goto set_root_pgd;
}
@@ -3774,9 +3772,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;

for (i = 0; i < 4; ++i) {
- hpa_t root = vcpu->arch.mmu->pae_root[i];
-
- MMU_WARN_ON(VALID_PAGE(root));
+ MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->pae_root[i]));
if (vcpu->arch.mmu->root_level == PT32E_ROOT_LEVEL) {
pdptr = vcpu->arch.mmu->get_pdptr(vcpu, i);
if (!(pdptr & PT_PRESENT_MASK)) {
@@ -3787,17 +3783,11 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
if (mmu_check_root(vcpu, root_gfn))
return 1;
}
- spin_lock(&vcpu->kvm->mmu_lock);
- if (make_mmu_pages_available(vcpu) < 0) {
- spin_unlock(&vcpu->kvm->mmu_lock);
- return -ENOSPC;
- }
- sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30, PT32_ROOT_LEVEL,
- 0, ACC_ALL);
- root = __pa(sp->spt);
- ++sp->root_count;
- spin_unlock(&vcpu->kvm->mmu_lock);

+ root = mmu_alloc_root(vcpu, root_gfn, i << 30,
+ PT32_ROOT_LEVEL, false);
+ if (!VALID_PAGE(root))
+ return -ENOSPC;
vcpu->arch.mmu->pae_root[i] = root | pm_mask;
}
vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root);
--
2.26.0
\
 
 \ /
  Last update: 2020-04-28 04:38    [W:0.075 / U:1.512 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site