lkml.org 
[lkml]   [2015]   [May]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 15/15] KVM: VMX: fully implement guest MTRR virtualization
    Date
    Currently guest MTRR is completely prohibited if cache snoop is supported on
    IOMMU (!noncoherent_dma) and host does the emulation based on the knowledge
    from host side, however, host side is not the good point to know
    what the purpose of guest is. A good example is that pass-throughed VGA
    frame buffer is not always UC as host expected

    This patchset enables full MTRR virtualization and currently only works on
    Intel EPT architecture

    Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
    ---
    arch/x86/include/asm/kvm_host.h | 2 +-
    arch/x86/kvm/mmu.c | 3 +--
    arch/x86/kvm/mtrr.c | 3 +--
    arch/x86/kvm/svm.c | 2 +-
    arch/x86/kvm/vmx.c | 28 ++++------------------------
    5 files changed, 8 insertions(+), 30 deletions(-)

    diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
    index 5be8f2e..b34de27 100644
    --- a/arch/x86/include/asm/kvm_host.h
    +++ b/arch/x86/include/asm/kvm_host.h
    @@ -806,7 +806,7 @@ struct kvm_x86_ops {
    void (*sync_pir_to_irr)(struct kvm_vcpu *vcpu);
    int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
    int (*get_tdp_level)(void);
    - u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
    + u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn);
    int (*get_lpage_level)(void);
    bool (*rdtscp_supported)(void);
    bool (*invpcid_supported)(void);
    diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
    index c8c2a90..828fcd6 100644
    --- a/arch/x86/kvm/mmu.c
    +++ b/arch/x86/kvm/mmu.c
    @@ -2496,8 +2496,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
    if (level > PT_PAGE_TABLE_LEVEL)
    spte |= PT_PAGE_SIZE_MASK;
    if (tdp_enabled)
    - spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
    - kvm_is_reserved_pfn(pfn));
    + spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn);

    if (host_writable)
    spte |= SPTE_HOST_WRITEABLE;
    diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
    index 703a66b..bf84218 100644
    --- a/arch/x86/kvm/mtrr.c
    +++ b/arch/x86/kvm/mtrr.c
    @@ -259,8 +259,7 @@ static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
    gfn_t start, end;
    int index;

    - if (msr == MSR_IA32_CR_PAT || !tdp_enabled ||
    - !kvm_arch_has_noncoherent_dma(vcpu->kvm))
    + if (msr == MSR_IA32_CR_PAT || !tdp_enabled)
    return;

    if (!mtrr_state->mtrr_enabled && msr != MSR_MTRRdefType)
    diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
    index b9f9e10..23dd78a 100644
    --- a/arch/x86/kvm/svm.c
    +++ b/arch/x86/kvm/svm.c
    @@ -4075,7 +4075,7 @@ static bool svm_cpu_has_accelerated_tpr(void)
    return false;
    }

    -static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
    +static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn)
    {
    return 0;
    }
    diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
    index fe7a589..78b77be 100644
    --- a/arch/x86/kvm/vmx.c
    +++ b/arch/x86/kvm/vmx.c
    @@ -8626,31 +8626,11 @@ static int get_ept_level(void)
    return VMX_EPT_DEFAULT_GAW + 1;
    }

    -static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
    -{
    - u64 ret;
    -
    - /* For VT-d and EPT combination
    - * 1. MMIO: always map as UC
    - * 2. EPT with VT-d:
    - * a. VT-d without snooping control feature: can't guarantee the
    - * result, try to trust guest.
    - * b. VT-d with snooping control feature: snooping control feature of
    - * VT-d engine can guarantee the cache correctness. Just set it
    - * to WB to keep consistent with host. So the same as item 3.
    - * 3. EPT without VT-d: always map as WB and set IPAT=1 to keep
    - * consistent with host MTRR
    - */
    - if (is_mmio)
    - ret = MTRR_TYPE_UNCACHABLE << VMX_EPT_MT_EPTE_SHIFT;
    - else if (kvm_arch_has_noncoherent_dma(vcpu->kvm))
    - ret = kvm_mtrr_get_guest_memory_type(vcpu, gfn) <<
    - VMX_EPT_MT_EPTE_SHIFT;
    - else
    - ret = (MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT)
    - | VMX_EPT_IPAT_BIT;
    +static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn)
    +{
    + u8 type = kvm_mtrr_get_guest_memory_type(vcpu, gfn);

    - return ret;
    + return type << VMX_EPT_MT_EPTE_SHIFT;
    }

    static int vmx_get_lpage_level(void)
    --
    2.1.0


    \
     
     \ /
      Last update: 2015-05-30 13:41    [W:2.336 / U:0.576 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site