From f2db946ad23967633bcc52b94dd8224e50d0b54b Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 9 Jun 2017 12:49:56 +0100
Subject: [PATCH 174/174] KVM: arm64: Log an error if trapping a
write-to-read-only GICv3 access
Patch-mainline: Submitted, https://www.spinics.net/lists/arm-kernel/msg587082.html
References: bsc#1031492
A write-to-read-only GICv3 access should UNDEF at EL1. But since
we're in complete paranoia-land with broken CPUs, let's assume the
worse and gracefully handle the case.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/arm64/kvm/sys_regs.c | 15 +++++++++++++++
virt/kvm/arm/hyp/vgic-v3-sr.c | 6 ++++++
2 files changed, 21 insertions(+)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 8d51c07..7786288 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -65,6 +65,16 @@ static bool read_from_write_only(struct kvm_vcpu *vcpu,
return false;
}
+static bool write_to_read_only(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *params,
+ const struct sys_reg_desc *r)
+{
+ WARN_ONCE(1, "Unexpected sys_reg write to read-only register\n");
+ print_sys_reg_instr(params);
+ kvm_inject_undefined(vcpu);
+ return false;
+}
+
/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
static u32 cache_levels;
@@ -954,10 +964,15 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_VBAR_EL1), NULL, reset_val, VBAR_EL1, 0 },
+ { SYS_DESC(SYS_ICC_IAR0_EL1), write_to_read_only },
{ SYS_DESC(SYS_ICC_EOIR0_EL1), read_from_write_only },
+ { SYS_DESC(SYS_ICC_HPPIR0_EL1), write_to_read_only },
{ SYS_DESC(SYS_ICC_DIR_EL1), read_from_write_only },
+ { SYS_DESC(SYS_ICC_RPR_EL1), write_to_read_only },
{ SYS_DESC(SYS_ICC_SGI1R_EL1), access_gic_sgi },
+ { SYS_DESC(SYS_ICC_IAR1_EL1), write_to_read_only },
{ SYS_DESC(SYS_ICC_EOIR1_EL1), read_from_write_only },
+ { SYS_DESC(SYS_ICC_HPPIR1_EL1), write_to_read_only },
{ SYS_DESC(SYS_ICC_SRE_EL1), access_gic_sre },
{ SYS_DESC(SYS_CONTEXTIDR_EL1), access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
index b26ce58..79e3c2d 100644
--- a/virt/kvm/arm/hyp/vgic-v3-sr.c
+++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
@@ -976,6 +976,8 @@ int __hyp_text __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu)
switch (sysreg) {
case SYS_ICC_IAR0_EL1:
case SYS_ICC_IAR1_EL1:
+ if (unlikely(!is_read))
+ return 0;
fn = __vgic_v3_read_iar;
break;
case SYS_ICC_EOIR0_EL1:
@@ -1026,6 +1028,8 @@ int __hyp_text __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu)
break;
case SYS_ICC_HPPIR0_EL1:
case SYS_ICC_HPPIR1_EL1:
+ if (unlikely(!is_read))
+ return 0;
fn = __vgic_v3_read_hppir;
break;
case SYS_ICC_GRPEN0_EL1:
@@ -1046,6 +1050,8 @@ int __hyp_text __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu)
fn = __vgic_v3_write_dir;
break;
case SYS_ICC_RPR_EL1:
+ if (unlikely(!is_read))
+ return 0;
fn = __vgic_v3_read_rpr;
break;
case SYS_ICC_CTLR_EL1:
--
1.8.5.6