[PATCH 13/15] KVM: SVM: Add and use svm_register_cache_reset()

Lai Jiangshan
2021-11-08T12:45:50Z

From: Lai Jiangshan <laijs@linux.alibaba.com>

It resets all the appropriate bits like vmx.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/kvm/svm/svm.c | 3 +--
arch/x86/kvm/svm/svm.h | 26 ++++++++++++++++++++++++++
2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b7da66935e72..ba9cfddd2875 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3969,8 +3969,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)

svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
vmcb_mark_all_clean(svm->vmcb);
-
- kvm_register_clear_available(vcpu, VCPU_EXREG_PDPTR);
+ svm_register_cache_reset(vcpu);

/*
* We need to handle MC intercepts here before the vcpu has a chance to
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 0d7bbe548ac3..1cf5d5e2d0cd 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -274,6 +274,32 @@ static inline bool vmcb_is_dirty(struct vmcb *vmcb, int bit)
return !test_bit(bit, (unsigned long *)&vmcb->control.clean);
}

+static inline void svm_register_cache_reset(struct kvm_vcpu *vcpu)
+{
+/*
+ * SVM_REGS_AVAIL_SET - The set of registers that will be updated in cache on
+ * demand. Other registers not listed here are synced to
+ * the cache immediately after VM-Exit.
+ *
+ * SVM_REGS_DIRTY_SET - The set of registers that might be outdated in
+ * architecture. Other registers not listed here are synced
+ * to the architecture immediately when modifying.
+ *
+ * Special case: VCPU_EXREG_CR3 should be in this set due
+ * to the fact. But KVM_REQ_LOAD_MMU_PGD is always
+ * requested when the cache vcpu->arch.cr3 is changed and
+ * svm_load_mmu_pgd() always syncs the new CR3 value into
+ * the architecture. So the dirty information of
+ * VCPU_EXREG_CR3 is not used which means VCPU_EXREG_CR3
+ * isn't required to be put in this set.
+ */
+#define SVM_REGS_AVAIL_SET (1 << VCPU_EXREG_PDPTR)
+#define SVM_REGS_DIRTY_SET (0)
+
+ vcpu->arch.regs_avail &= ~SVM_REGS_AVAIL_SET;
+ vcpu->arch.regs_dirty &= ~SVM_REGS_DIRTY_SET;
+}
+
static inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)
{
return container_of(vcpu, struct vcpu_svm, vcpu);
--
2.19.1.6.gb485710b