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backport: KVM: x86: introduce is_pae_paging

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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2019-11-12 13:33:39 +01:00
parent 7481faa0a8
commit 584fbee1dd
2 changed files with 105 additions and 50 deletions
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105
patches/kernel/0008-KVM-x86-introduce-is_pae_paging.patch Normal file
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@ -0,0 +1,105 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 6 Jun 2019 18:52:44 +0200
Subject: [PATCH] KVM: x86: introduce is_pae_paging
Checking for 32-bit PAE is quite common around code that fiddles with
the PDPTRs. Add a function to compress all checks into a single
invocation.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit bf03d4f9334728bf7c8ffc7de787df48abd6340e)
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
arch/x86/kvm/vmx/nested.c | 3 +--
arch/x86/kvm/vmx/vmx.c | 4 ++--
arch/x86/kvm/x86.c | 8 ++++----
arch/x86/kvm/x86.h | 5 +++++
4 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index d7c52e748966..7bb5801b5e11 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -944,8 +944,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne
* If PAE paging and EPT are both on, CR3 is not used by the CPU and
* must not be dereferenced.
*/
- if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu) &&
- !nested_ept) {
+ if (is_pae_paging(vcpu) && !nested_ept) {
if (!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) {
*entry_failure_code = ENTRY_FAIL_PDPTE;
return 1;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d27b75c41982..923d0f1b7a05 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2737,7 +2737,7 @@ static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
(unsigned long *)&vcpu->arch.regs_dirty))
return;
- if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
+ if (is_pae_paging(vcpu)) {
vmcs_write64(GUEST_PDPTR0, mmu->pdptrs[0]);
vmcs_write64(GUEST_PDPTR1, mmu->pdptrs[1]);
vmcs_write64(GUEST_PDPTR2, mmu->pdptrs[2]);
@@ -2749,7 +2749,7 @@ void ept_save_pdptrs(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
- if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
+ if (is_pae_paging(vcpu)) {
mmu->pdptrs[0] = vmcs_read64(GUEST_PDPTR0);
mmu->pdptrs[1] = vmcs_read64(GUEST_PDPTR1);
mmu->pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f832fa5011cd..5d2a2ca5b60d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -724,7 +724,7 @@ bool pdptrs_changed(struct kvm_vcpu *vcpu)
gfn_t gfn;
int r;
- if (is_long_mode(vcpu) || !is_pae(vcpu) || !is_paging(vcpu))
+ if (!is_pae_paging(vcpu))
return false;
if (!test_bit(VCPU_EXREG_PDPTR,
@@ -967,8 +967,8 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
if (is_long_mode(vcpu) &&
(cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)))
return 1;
- else if (is_pae(vcpu) && is_paging(vcpu) &&
- !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
+ else if (is_pae_paging(vcpu) &&
+ !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
return 1;
kvm_mmu_new_cr3(vcpu, cr3, skip_tlb_flush);
@@ -8554,7 +8554,7 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
kvm_update_cpuid(vcpu);
idx = srcu_read_lock(&vcpu->kvm->srcu);
- if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu)) {
+ if (is_pae_paging(vcpu)) {
load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
mmu_reset_needed = 1;
}
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 7e89ed889707..03de3f3c830c 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -139,6 +139,11 @@ static inline int is_paging(struct kvm_vcpu *vcpu)
return likely(kvm_read_cr0_bits(vcpu, X86_CR0_PG));
}
+static inline bool is_pae_paging(struct kvm_vcpu *vcpu)
+{
+ return !is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu);
+}
+
static inline u32 bit(int bitno)
{
return 1 << (bitno & 31);

50
patches/kernel/0008-Revert-KVM-x86-Manually-calculate-reserved-bits-when.patch
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@ -1,50 +0,0 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Lamprecht <t.lamprecht@proxmox.com>
Date: Mon, 11 Nov 2019 11:12:32 +0100
Subject: [PATCH] Revert "KVM: x86: Manually calculate reserved bits when
loading PDPTRS"
This was back-ported from the 5.4 merge window, on kernels <5.3 it
makes issues with old intel CPUs (like more than ~ 10 years ago
released ones).
Reverse bisect does not show a clear commit which would fix that, so
revert this for now.
This reverts commit 208007519a7385a57b0c0a3c180142a521594876.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
arch/x86/kvm/x86.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f832fa5011cd..fd00cfdfb6c3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -672,14 +672,8 @@ static int kvm_read_nested_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
data, offset, len, access);
}
-static inline u64 pdptr_rsvd_bits(struct kvm_vcpu *vcpu)
-{
- return rsvd_bits(cpuid_maxphyaddr(vcpu), 63) | rsvd_bits(5, 8) |
- rsvd_bits(1, 2);
-}
-
/*
- * Load the pae pdptrs. Return 1 if they are all valid, 0 otherwise.
+ * Load the pae pdptrs. Return true is they are all valid.
*/
int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
{
@@ -698,7 +692,8 @@ int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
}
for (i = 0; i < ARRAY_SIZE(pdpte); ++i) {
if ((pdpte[i] & PT_PRESENT_MASK) &&
- (pdpte[i] & pdptr_rsvd_bits(vcpu))) {
+ (pdpte[i] &
+ vcpu->arch.mmu->guest_rsvd_check.rsvd_bits_mask[0][2])) {
ret = 0;
goto out;
}