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KVM: x86: extend struct kvm_vcpu_pv_apf_data with token info

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Currently, APF mechanism relies on the #PF abuse where the token is being
passed through CR2. If we switch to using interrupts to deliver page-ready
notifications we need a different way to pass the data. Extent the existing
'struct kvm_vcpu_pv_apf_data' with token information for page-ready
notifications.

While on it, rename 'reason' to 'flags'. This doesn't change the semantics
as we only have reasons '1' and '2' and these can be treated as bit flags
but KVM_PV_REASON_PAGE_READY is going away with interrupt based delivery
making 'reason' name misleading.

The newly introduced apf_put_user_ready() temporary puts both flags and
token information, this will be changed to put token only when we switch
to interrupt based notifications.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200525144125.143875-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov
2020-05-25 16:41:17 +02:00
committed by Paolo Bonzini
parent 84b09f33a5
commit 68fd66f100
10 changed files with 36 additions and 25 deletions
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16
arch/x86/kernel/kvm.c
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@@ -218,23 +218,23 @@ again:
}
EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
u32 kvm_read_and_reset_pf_reason(void)
u32 kvm_read_and_reset_apf_flags(void)
{
u32 reason = 0;
u32 flags = 0;
if (__this_cpu_read(apf_reason.enabled)) {
reason = __this_cpu_read(apf_reason.reason);
__this_cpu_write(apf_reason.reason, 0);
flags = __this_cpu_read(apf_reason.flags);
__this_cpu_write(apf_reason.flags, 0);
}
return reason;
return flags;
}
EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
NOKPROBE_SYMBOL(kvm_read_and_reset_pf_reason);
EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags);
NOKPROBE_SYMBOL(kvm_read_and_reset_apf_flags);
bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
{
u32 reason = kvm_read_and_reset_pf_reason();
u32 reason = kvm_read_and_reset_apf_flags();
switch (reason) {
case KVM_PV_REASON_PAGE_NOT_PRESENT: