linux-kernel - [PATCH 104/104] KVM: Skip pio instruction when it is emulated, not executed

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <11900179493572-git-send-email-avi@qumranet.com>
Date:	Mon, 17 Sep 2007 10:32:26 +0200
From:	Avi Kivity <avi@...ranet.com>
To:	kvm-devel@...ts.sourceforge.net
Cc:	linux-kernel@...r.kernel.org, Avi Kivity <avi@...ranet.com>
Subject: [PATCH 104/104] KVM: Skip pio instruction when it is emulated, not executed

If we defer updating rip until pio instructions are executed, we have a
problem with reset:  a pio reset updates rip, and when the instruction
completes we skip the emulated instruction, pointing rip somewhere completely
unrelated.

Fix by updating rip when we see decode the instruction, not after emulation.

Signed-off-by: Avi Kivity <avi@...ranet.com>
---
 drivers/kvm/kvm_main.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 99e4917..4adb4c5 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1815,8 +1815,6 @@ static int complete_pio(struct kvm_vcpu *vcpu)
 	io->count -= io->cur_count;
 	io->cur_count = 0;
 
-	if (!io->count)
-		kvm_x86_ops->skip_emulated_instruction(vcpu);
 	return 0;
 }
 
@@ -1876,6 +1874,8 @@ int kvm_emulate_pio (struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
 	memcpy(vcpu->pio_data, &vcpu->regs[VCPU_REGS_RAX], 4);
 	kvm_x86_ops->decache_regs(vcpu);
 
+	kvm_x86_ops->skip_emulated_instruction(vcpu);
+
 	pio_dev = vcpu_find_pio_dev(vcpu, port);
 	if (pio_dev) {
 		kernel_pio(pio_dev, vcpu, vcpu->pio_data);
@@ -1938,6 +1938,9 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
 	vcpu->run->io.count = now;
 	vcpu->pio.cur_count = now;
 
+	if (vcpu->pio.cur_count == vcpu->pio.count)
+		kvm_x86_ops->skip_emulated_instruction(vcpu);
+
 	for (i = 0; i < nr_pages; ++i) {
 		mutex_lock(&vcpu->kvm->lock);
 		page = gva_to_page(vcpu, address + i * PAGE_SIZE);
-- 
1.5.3

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/