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From a4337b660fe26046e81471186dc393ca77371b83 Mon Sep 17 00:00:00 2001
From: Nikita Leshenko <nikita.leshchenko@oracle.com>
Date: Sun, 5 Nov 2017 15:52:33 +0200
Subject: [PATCH 09/33] KVM: x86: ioapic: Preserve read-only values in the
redirection table
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
[ Upstream commit b200dded0a6974a3b69599832b2203483920ab25 ]
According to 82093AA (IOAPIC) manual, Remote IRR and Delivery Status are
read-only. QEMU implements the bits as RO in commit 479c2a1cb7fb
("ioapic: keep RO bits for IOAPIC entry").
Signed-off-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/ioapic.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
index 4b573c8..5f810bb 100644
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -278,6 +278,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
{
unsigned index;
bool mask_before, mask_after;
+ int old_remote_irr, old_delivery_status;
union kvm_ioapic_redirect_entry *e;
switch (ioapic->ioregsel) {
@@ -300,6 +301,9 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
return;
e = &ioapic->redirtbl[index];
mask_before = e->fields.mask;
+ /* Preserve read-only fields */
+ old_remote_irr = e->fields.remote_irr;
+ old_delivery_status = e->fields.delivery_status;
if (ioapic->ioregsel & 1) {
e->bits &= 0xffffffff;
e->bits |= (u64) val << 32;
@@ -307,6 +311,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
e->bits &= ~0xffffffffULL;
e->bits |= (u32) val;
}
+ e->fields.remote_irr = old_remote_irr;
+ e->fields.delivery_status = old_delivery_status;
/*
* Some OSes (Linux, Xen) assume that Remote IRR bit will
--
2.7.4
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