On 10/04/2010 05:56 PM, Gleb Natapov wrote:
Guest enables async PF vcpu functionality using this MSR.
return NON_PRESENT;
+
+MSR_KVM_ASYNC_PF_EN: 0x4b564d02
+ data: Bits 63-6 hold 64-byte aligned physical address of a 32bit memory
Given that it must be aligned anyway, we can require it to be a 64-byte
region and also require that the guest zero it before writing the MSR.
That will give us a little more flexibility in the future.
+ area which must be in guest RAM. Bits 5-1 are reserved and should be
+ zero. Bit 0 is 1 when asynchronous page faults are enabled on the vcpu
+ 0 when disabled.
+
+ Physical address points to 32 bit memory location that will be written
+ to by the hypervisor at the time of asynchronous page fault injection to
+ indicate type of asynchronous page fault. Value of 1 means that the page
+ referred to by the page fault is not present. Value 2 means that the
+ page is now available.
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b9f263e..de31551 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -417,6 +417,8 @@ struct kvm_vcpu_arch {
struct {
gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)];
+ struct gfn_to_hva_cache data;
+ u64 msr_val;
} apf;
};
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index e3faaaf..8662ae0 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -20,6 +20,7 @@
* are available. The use of 0x11 and 0x12 is deprecated
*/
#define KVM_FEATURE_CLOCKSOURCE2 3
+#define KVM_FEATURE_ASYNC_PF 4
/* The last 8 bits are used to indicate how to interpret the flags field
* in pvclock structure. If no bits are set, all flags are ignored.
@@ -32,9 +33,12 @@
/* Custom MSRs falls in the range 0x4b564d00-0x4b564dff */
#define MSR_KVM_WALL_CLOCK_NEW 0x4b564d00
#define MSR_KVM_SYSTEM_TIME_NEW 0x4b564d01
+#define MSR_KVM_ASYNC_PF_EN 0x4b564d02
#define KVM_MAX_MMU_OP_BATCH 32
+#define KVM_ASYNC_PF_ENABLED (1<< 0)
+
/* Operations for KVM_HC_MMU_OP */
#define KVM_MMU_OP_WRITE_PTE 1
#define KVM_MMU_OP_FLUSH_TLB 2
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 48fd59d..3e123ab 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -782,12 +782,12 @@ EXPORT_SYMBOL_GPL(kvm_get_dr);
* kvm-specific. Those are put in the beginning of the list.
*/
-#define KVM_SAVE_MSRS_BEGIN 7
+#define KVM_SAVE_MSRS_BEGIN 8
static u32 msrs_to_save[] = {
MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
- HV_X64_MSR_APIC_ASSIST_PAGE,
+ HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN,
MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
MSR_STAR,
#ifdef CONFIG_X86_64
@@ -1425,6 +1425,29 @@ static int set_msr_hyperv(struct kvm_vcpu *vcpu, u32
msr, u64 data)
return 0;
}
+static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
+{
+ gpa_t gpa = data& ~0x3f;
+
+ /* Bits 1:5 are resrved, Should be zero */
+ if (data& 0x3e)
+ return 1;
+
+ vcpu->arch.apf.msr_val = data;
+
+ if (!(data& KVM_ASYNC_PF_ENABLED)) {
+ kvm_clear_async_pf_completion_queue(vcpu);
May be a lengthy synchronous operation. I guess we don't care.
+ memset(vcpu->arch.apf.gfns, 0xff, sizeof vcpu->arch.apf.gfns);
That memset again.
+ return 0;
+ }
+
+ if (kvm_gfn_to_hva_cache_init(vcpu->kvm,&vcpu->arch.apf.data, gpa))
+ return 1;
Note: we need to handle the memory being removed from underneath
kvm_gfn_to_hve_cache(). Given that, we can just make
kvm_gfn_to_hva_cache_init() return void. "success" means nothing when
future changes can invalidate it.
+
+ kvm_async_pf_wakeup_all(vcpu);
Why is this needed? If all apfs are flushed at disable time, what do we
need to wake up?
Need to list the MSR for save/restore/reset.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
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