Gleb Natapov wrote on 2012-12-20:
> On Mon, Dec 17, 2012 at 01:30:50PM +0800, Yang Zhang wrote:
>> basically to benefit from apicv, we need clear MSR bitmap for
>> corresponding x2apic MSRs:
>> 0x800 - 0x8ff: no read intercept for apicv register virtualization
>> TPR,EOI,SELF-IPI: no write intercept for virtual interrupt delivery
> We do not set "Virtualize x2APIC mode" bit in secondary execution
> control. If I read the spec correctly without that those MSR read/writes
> will go straight to physical local APIC.
Right. Now it cannot get benefit, but we may enable it in future and then we can benefit from it.
>> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>> Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
>> ---
>> arch/x86/kvm/vmx.c | 62
>> ++++++++++++++++++++++++++++++++++++++++++++++------ 1 files changed,
>> 55 insertions(+), 7 deletions(-)
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index be66c3e..9b5e7a2 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -3773,7 +3773,10 @@ static void free_vpid(struct vcpu_vmx *vmx)
>> spin_unlock(&vmx_vpid_lock);
>> }
>> -static void __vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
>> u32 msr) +#define MSR_TYPE_R 1 +#define MSR_TYPE_W 2 +static void
>> __vmx_disable_intercept_for_msr(unsigned long *msr_bitmap, + u32
>> msr, int type)
>> {
>> int f = sizeof(unsigned long);
>> @@ -3786,20 +3789,52 @@ static void
> __vmx_disable_intercept_for_msr(unsigned long *msr_bitmap, u32 msr)
>> * We can control MSRs 0x00000000-0x00001fff and 0xc0000000-0xc0001fff.
>> */
>> if (msr <= 0x1fff) {
>> - __clear_bit(msr, msr_bitmap + 0x000 / f); /* read-low */
>> - __clear_bit(msr, msr_bitmap + 0x800 / f); /* write-low */
>> + if (type & MSR_TYPE_R)
>> + /* read-low */
>> + __clear_bit(msr, msr_bitmap + 0x000 / f);
>> +
>> + if (type & MSR_TYPE_W)
>> + /* write-low */
>> + __clear_bit(msr, msr_bitmap + 0x800 / f);
>> +
>> } else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {
>> msr &= 0x1fff;
>> - __clear_bit(msr, msr_bitmap + 0x400 / f); /* read-high */
>> - __clear_bit(msr, msr_bitmap + 0xc00 / f); /* write-high */
>> + if (type & MSR_TYPE_R)
>> + /* read-high */
>> + __clear_bit(msr, msr_bitmap + 0x400 / f);
>> +
>> + if (type & MSR_TYPE_W)
>> + /* write-high */
>> + __clear_bit(msr, msr_bitmap + 0xc00 / f);
>> +
>> }
>> }
>>
>> static void vmx_disable_intercept_for_msr(u32 msr, bool longmode_only)
>> {
>> if (!longmode_only)
>> - __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy, msr);
>> - __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode, msr);
>> + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy, + msr,
>> MSR_TYPE_R | MSR_TYPE_W);
>> + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode, + msr,
>> MSR_TYPE_R | MSR_TYPE_W); +} + +static void
>> vmx_disable_intercept_for_msr_read(u32 msr, bool longmode_only) +{ + if
>> (!longmode_only)
>> + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy, + msr,
>> MSR_TYPE_R); + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode,
>> + msr, MSR_TYPE_R); +} + +static void
>> vmx_disable_intercept_for_msr_write(u32 msr, bool longmode_only) +{
>> + if (!longmode_only)
>> + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy, + msr,
>> MSR_TYPE_W); + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode,
>> + msr, MSR_TYPE_W);
>> }
>>
>> /* @@ -7633,6 +7668,19 @@ static int __init vmx_init(void)
>> vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
>> vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
>> + if (enable_apicv_reg_vid) {
>> + int msr;
>> + for (msr = 0x800; msr <= 0x8ff; msr++)
>> + vmx_disable_intercept_for_msr_read(msr, false);
>> +
>> + /* TPR */
>> + vmx_disable_intercept_for_msr_write(0x808, false);
>> + /* EOI */
>> + vmx_disable_intercept_for_msr_write(0x80b, false);
>> + /* SELF-IPI */
>> + vmx_disable_intercept_for_msr_write(0x83f, false);
>> + }
>> +
>> if (enable_ept) {
>> kvm_mmu_set_mask_ptes(0ull,
>> (enable_ept_ad_bits) ? VMX_EPT_ACCESS_BIT : 0ull,
>> --
>> 1.7.1
>
> --
> Gleb.
Best regards,
Yang
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