From: Willy Tarreau <w@1wt.eu>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net
Cc: "James Hogan" <james.hogan@imgtec.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Ralf Baechle" <ralf@linux-mips.org>,
linux-mips@linux-mips.org, kvm@vger.kernel.org,
"Willy Tarreau" <w@1wt.eu>
Subject: [PATCH 3.10 026/319] KVM: MIPS: Make ERET handle ERL before EXL
Date: Sun, 5 Feb 2017 20:21:04 +0100 [thread overview]
Message-ID: <1486322467-7968-4-git-send-email-w@1wt.eu> (raw)
In-Reply-To: <1486322467-7968-1-git-send-email-w@1wt.eu>
From: James Hogan <james.hogan@imgtec.com>
commit ede5f3e7b54a4347be4d8525269eae50902bd7cd upstream.
The ERET instruction to return from exception is used for returning from
exception level (Status.EXL) and error level (Status.ERL). If both bits
are set however we should be returning from ERL first, as ERL can
interrupt EXL, for example when an NMI is taken. KVM however checks EXL
first.
Fix the order of the checks to match the pseudocode in the instruction
set manual.
Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim KrÄmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
arch/mips/kvm/kvm_mips_emul.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c
index 4cfb5bd..7162854 100644
--- a/arch/mips/kvm/kvm_mips_emul.c
+++ b/arch/mips/kvm/kvm_mips_emul.c
@@ -254,15 +254,15 @@ enum emulation_result kvm_mips_emul_eret(struct kvm_vcpu *vcpu)
struct mips_coproc *cop0 = vcpu->arch.cop0;
enum emulation_result er = EMULATE_DONE;
- if (kvm_read_c0_guest_status(cop0) & ST0_EXL) {
+ if (kvm_read_c0_guest_status(cop0) & ST0_ERL) {
+ kvm_clear_c0_guest_status(cop0, ST0_ERL);
+ vcpu->arch.pc = kvm_read_c0_guest_errorepc(cop0);
+ } else if (kvm_read_c0_guest_status(cop0) & ST0_EXL) {
kvm_debug("[%#lx] ERET to %#lx\n", vcpu->arch.pc,
kvm_read_c0_guest_epc(cop0));
kvm_clear_c0_guest_status(cop0, ST0_EXL);
vcpu->arch.pc = kvm_read_c0_guest_epc(cop0);
- } else if (kvm_read_c0_guest_status(cop0) & ST0_ERL) {
- kvm_clear_c0_guest_status(cop0, ST0_ERL);
- vcpu->arch.pc = kvm_read_c0_guest_errorepc(cop0);
} else {
printk("[%#lx] ERET when MIPS_SR_EXL|MIPS_SR_ERL == 0\n",
vcpu->arch.pc);
--
2.8.0.rc2.1.gbe9624a
next prev parent reply other threads:[~2017-02-05 19:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-05 19:21 [PATCH 3.10 023/319] KVM: MIPS: Precalculate MMIO load resume PC Willy Tarreau
2017-02-05 19:21 ` [PATCH 3.10 024/319] KVM: MIPS: Drop other CPU ASIDs on guest MMU changes Willy Tarreau
2017-02-05 19:21 ` [PATCH 3.10 025/319] KVM: nVMX: postpone VMCS changes on MSR_IA32_APICBASE write Willy Tarreau
2017-02-05 19:21 ` Willy Tarreau [this message]
2017-02-05 19:21 ` [PATCH 3.10 027/319] KVM: x86: fix wbinvd_dirty_mask use-after-free Willy Tarreau
2017-02-05 19:21 ` [PATCH 3.10 028/319] KVM: x86: fix missed SRCU usage in kvm_lapic_set_vapic_addr Willy Tarreau
2017-02-05 19:21 ` [PATCH 3.10 029/319] KVM: Disable irq while unregistering user notifier Willy Tarreau
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