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From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Wanpeng Li <wanpengli@tencent.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	x86@kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, Xiaoyao Li <xiaoyao.li@intel.com>
Subject: [PATCH v2 2/2] KVM: x86: Improve documentation of MSR_KVM_ASYNC_PF_EN
Date: Wed, 25 Oct 2023 01:59:14 -0400	[thread overview]
Message-ID: <20231025055914.1201792-3-xiaoyao.li@intel.com> (raw)
In-Reply-To: <20231025055914.1201792-1-xiaoyao.li@intel.com>

Fix some incorrect statement of MSR_KVM_ASYNC_PF_EN documentation and
state clearly the token in 'struct kvm_vcpu_pv_apf_data' of 'page ready'
event is matchted with the token in CR2 in 'page not present' event.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 Documentation/virt/kvm/x86/msr.rst | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/Documentation/virt/kvm/x86/msr.rst b/Documentation/virt/kvm/x86/msr.rst
index f6d70f99a1a7..3aecf2a70e7b 100644
--- a/Documentation/virt/kvm/x86/msr.rst
+++ b/Documentation/virt/kvm/x86/msr.rst
@@ -193,8 +193,8 @@ data:
 	Asynchronous page fault (APF) control MSR.
 
 	Bits 63-6 hold 64-byte aligned physical address of a 64 byte memory area
-	which must be in guest RAM and must be zeroed. This memory is expected
-	to hold a copy of the following structure::
+	which must be in guest RAM. This memory is expected to hold the
+	following structure::
 
 	  struct kvm_vcpu_pv_apf_data {
 		/* Used for 'page not present' events delivered via #PF */
@@ -231,14 +231,14 @@ data:
 	as regular page fault, guest must reset 'flags' to '0' before it does
 	something that can generate normal page fault.
 
-	Bytes 5-7 of 64 byte memory location ('token') will be written to by the
+	Bytes 4-7 of 64 byte memory location ('token') will be written to by the
 	hypervisor at the time of APF 'page ready' event injection. The content
-	of these bytes is a token which was previously delivered as 'page not
-	present' event. The event indicates the page in now available. Guest is
-	supposed to write '0' to 'token' when it is done handling 'page ready'
-	event and to write 1' to MSR_KVM_ASYNC_PF_ACK after clearing the location;
-	writing to the MSR forces KVM to re-scan its queue and deliver the next
-	pending notification.
+	of these bytes is a token which was previously delivered in CR2 as
+	'page not present' event. The event indicates the page is now available.
+	Guest is supposed to write '0' to 'token' when it is done handling
+	'page ready' event and to write '1' to MSR_KVM_ASYNC_PF_ACK after
+	clearing the location; writing to the MSR forces KVM to re-scan its
+	queue and deliver the next pending notification.
 
 	Note, MSR_KVM_ASYNC_PF_INT MSR specifying the interrupt vector for 'page
 	ready' APF delivery needs to be written to before enabling APF mechanism
-- 
2.34.1


  parent reply	other threads:[~2023-10-25  5:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-25  5:59 [PATCH v2 0/2] x86/asyncpf: Fixes the size of asyncpf PV data and related docs Xiaoyao Li
2023-10-25  5:59 ` [PATCH v2 1/2] x86/kvm/async_pf: Use separate percpu variable to track the enabling of asyncpf Xiaoyao Li
2023-10-25  9:10   ` Vitaly Kuznetsov
2023-10-25 14:22     ` Sean Christopherson
2023-10-30  5:47       ` Xiaoyao Li
2023-10-30 23:17         ` Sean Christopherson
2023-10-30  5:17     ` Xiaoyao Li
2023-10-25  5:59 ` Xiaoyao Li [this message]
2024-02-06 21:36 ` [PATCH v2 0/2] x86/asyncpf: Fixes the size of asyncpf PV data and related docs Sean Christopherson
2024-02-07  6:26   ` Xiaoyao Li

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