From efdfe536d8c643391e19d5726b072f82964bfbdb Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Wed, 13 May 2015 14:42:27 +0800 Subject: [PATCH] KVM: MMU: fix MTRR update Currently, whenever guest MTRR registers are changed kvm_mmu_reset_context is called to switch to the new root shadow page table, however, it's useless since: 1) the cache type is not cached into shadow page's attribute so that the original root shadow page will be reused 2) the cache type is set on the last spte, that means we should sync the last sptes when MTRR is changed This patch fixs this issue by drop all the spte in the gfn range which is being updated by MTRR Signed-off-by: Xiao Guangrong Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 24 +++++++++++++++++++ arch/x86/kvm/mmu.h | 1 + arch/x86/kvm/x86.c | 59 +++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 83 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index e718c76609f9..5bebec1191f1 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4525,6 +4525,30 @@ slot_handle_leaf(struct kvm *kvm, struct kvm_memory_slot *memslot, PT_PAGE_TABLE_LEVEL, lock_flush_tlb); } +void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + + slots = kvm_memslots(kvm); + + spin_lock(&kvm->mmu_lock); + kvm_for_each_memslot(memslot, slots) { + gfn_t start, end; + + start = max(gfn_start, memslot->base_gfn); + end = min(gfn_end, memslot->base_gfn + memslot->npages); + if (start >= end) + continue; + + slot_handle_level_range(kvm, memslot, kvm_zap_rmapp, + PT_PAGE_TABLE_LEVEL, PT_MAX_HUGEPAGE_LEVEL, + start, end - 1, true); + } + + spin_unlock(&kvm->mmu_lock); +} + static bool slot_rmap_write_protect(struct kvm *kvm, unsigned long *rmapp) { return __rmap_write_protect(kvm, rmapp, false); diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 72bb33f70c16..398d21c0f6dd 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -171,4 +171,5 @@ static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, } void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm); +void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end); #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index cde5d614ff0a..bbe184f07bf9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1852,6 +1852,63 @@ bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) } EXPORT_SYMBOL_GPL(kvm_mtrr_valid); +static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr) +{ + struct mtrr_state_type *mtrr_state = &vcpu->arch.mtrr_state; + unsigned char mtrr_enabled = mtrr_state->enabled; + gfn_t start, end, mask; + int index; + bool is_fixed = true; + + if (msr == MSR_IA32_CR_PAT || !tdp_enabled || + !kvm_arch_has_noncoherent_dma(vcpu->kvm)) + return; + + if (!(mtrr_enabled & 0x2) && msr != MSR_MTRRdefType) + return; + + switch (msr) { + case MSR_MTRRfix64K_00000: + start = 0x0; + end = 0x80000; + break; + case MSR_MTRRfix16K_80000: + start = 0x80000; + end = 0xa0000; + break; + case MSR_MTRRfix16K_A0000: + start = 0xa0000; + end = 0xc0000; + break; + case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000: + index = msr - MSR_MTRRfix4K_C0000; + start = 0xc0000 + index * (32 << 10); + end = start + (32 << 10); + break; + case MSR_MTRRdefType: + is_fixed = false; + start = 0x0; + end = ~0ULL; + break; + default: + /* variable range MTRRs. */ + is_fixed = false; + index = (msr - 0x200) / 2; + start = (((u64)mtrr_state->var_ranges[index].base_hi) << 32) + + (mtrr_state->var_ranges[index].base_lo & PAGE_MASK); + mask = (((u64)mtrr_state->var_ranges[index].mask_hi) << 32) + + (mtrr_state->var_ranges[index].mask_lo & PAGE_MASK); + mask |= ~0ULL << cpuid_maxphyaddr(vcpu); + + end = ((start & mask) | ~mask) + 1; + } + + if (is_fixed && !(mtrr_enabled & 0x1)) + return; + + kvm_zap_gfn_range(vcpu->kvm, gpa_to_gfn(start), gpa_to_gfn(end)); +} + static int set_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 data) { u64 *p = (u64 *)&vcpu->arch.mtrr_state.fixed_ranges; @@ -1885,7 +1942,7 @@ static int set_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 data) *pt = data; } - kvm_mmu_reset_context(vcpu); + update_mtrr(vcpu, msr); return 0; }