| 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
| ||
|
Message-Id: <1491232765-32501-9-git-send-email-mark.rutland@arm.com>
Date: Mon, 3 Apr 2017 16:19:24 +0100
From: Mark Rutland <mark.rutland@....com>
To: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org, arnd@...db.de,
catalin.marinas@....com, christoffer.dall@...aro.org,
jiong.wang@....com, kvmarm@...ts.cs.columbia.edu,
linux-arch@...r.kernel.org, marc.zyngier@....com,
mark.rutland@....com, suzuki.poulose@....com, will.deacon@....com
Subject: [RFC 8/9] arm64/kvm: context-switch PAC registers
If we have pointer authentication support, a guest may wish to use it.
This patch adds the infrastructure to allow it to do so.
This is sufficient for basic testing, but not for real-world usage. A
guest will still see pointer authentication support advertised in the ID
registers, and we will need to trap accesses to these to provide
santized values.
Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Christoffer Dall <christoffer.dall@...aro.org>
Cc: Marc Zyngier <marc.zyngier@....com>
Cc: kvmarm@...ts.cs.columbia.edu
---
arch/arm64/include/asm/kvm_emulate.h | 15 +++++++++++++
arch/arm64/include/asm/kvm_host.h | 12 ++++++++++
arch/arm64/kvm/hyp/sysreg-sr.c | 43 ++++++++++++++++++++++++++++++++++++
3 files changed, 70 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index f5ea0ba..0c3cb43 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -28,6 +28,8 @@
#include <asm/kvm_arm.h>
#include <asm/kvm_mmio.h>
#include <asm/ptrace.h>
+#include <asm/cpucaps.h>
+#include <asm/cpufeature.h>
#include <asm/cputype.h>
#include <asm/virt.h>
@@ -49,6 +51,19 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
vcpu->arch.hcr_el2 |= HCR_E2H;
if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features))
vcpu->arch.hcr_el2 &= ~HCR_RW;
+
+ /*
+ * Address auth and generic auth share the same enable bits, so we have
+ * to ensure both are uniform before we can enable support in a guest.
+ * Until we have the infrastructure to detect uniform absence of a
+ * feature, only permit the case when both are supported.
+ *
+ * Note that a guest will still see the feature in ID_AA64_ISAR1 until
+ * we introduce code to emulate the ID registers.
+ */
+ if (cpus_have_const_cap(ARM64_HAS_ADDRESS_AUTH) &&
+ cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH))
+ vcpu->arch.hcr_el2 |= (HCR_API | HCR_APK);
}
static inline unsigned long vcpu_get_hcr(struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e7705e7..b25f710 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -133,6 +133,18 @@ enum vcpu_sysreg {
PMSWINC_EL0, /* Software Increment Register */
PMUSERENR_EL0, /* User Enable Register */
+ /* Pointer Authentication Registers */
+ APIAKEYLO_EL1,
+ APIAKEYHI_EL1,
+ APIBKEYLO_EL1,
+ APIBKEYHI_EL1,
+ APDAKEYLO_EL1,
+ APDAKEYHI_EL1,
+ APDBKEYLO_EL1,
+ APDBKEYHI_EL1,
+ APGAKEYLO_EL1,
+ APGAKEYHI_EL1,
+
/* 32bit specific registers. Keep them at the end of the range */
DACR32_EL2, /* Domain Access Control Register */
IFSR32_EL2, /* Instruction Fault Status Register */
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 9341376..3440b42 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -18,6 +18,8 @@
#include <linux/compiler.h>
#include <linux/kvm_host.h>
+#include <asm/cpucaps.h>
+#include <asm/cpufeature.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_hyp.h>
@@ -31,6 +33,24 @@ static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { }
* pstate, and guest must save everything.
*/
+#define __save_ap_key(regs, key) \
+ regs[key ## KEYLO_EL1] = read_sysreg_s(SYS_ ## key ## KEYLO_EL1); \
+ regs[key ## KEYHI_EL1] = read_sysreg_s(SYS_ ## key ## KEYHI_EL1)
+
+static void __hyp_text __sysreg_save_ap_keys(struct kvm_cpu_context *ctxt)
+{
+ if (cpus_have_const_cap(ARM64_HAS_ADDRESS_AUTH)) {
+ __save_ap_key(ctxt->sys_regs, APIA);
+ __save_ap_key(ctxt->sys_regs, APIB);
+ __save_ap_key(ctxt->sys_regs, APDA);
+ __save_ap_key(ctxt->sys_regs, APDB);
+ }
+
+ if (cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH)) {
+ __save_ap_key(ctxt->sys_regs, APGA);
+ }
+}
+
static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
{
ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
@@ -41,6 +61,8 @@ static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
ctxt->gp_regs.regs.pc = read_sysreg_el2(elr);
ctxt->gp_regs.regs.pstate = read_sysreg_el2(spsr);
+
+ __sysreg_save_ap_keys(ctxt);
}
static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
@@ -84,6 +106,25 @@ void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
__sysreg_save_common_state(ctxt);
}
+#define __restore_ap_key(regs, key) \
+ write_sysreg_s(regs[key ## KEYLO_EL1], SYS_ ## key ## KEYLO_EL1); \
+ write_sysreg_s(regs[key ## KEYHI_EL1], SYS_ ## key ## KEYHI_EL1)
+
+static void __hyp_text __sysreg_restore_ap_keys(struct kvm_cpu_context *ctxt)
+{
+ if (cpus_have_const_cap(ARM64_HAS_ADDRESS_AUTH)) {
+ __restore_ap_key(ctxt->sys_regs, APIA);
+ __restore_ap_key(ctxt->sys_regs, APIB);
+ __restore_ap_key(ctxt->sys_regs, APDA);
+ __restore_ap_key(ctxt->sys_regs, APDB);
+ }
+
+ if (cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH)) {
+ __restore_ap_key(ctxt->sys_regs, APGA);
+ }
+}
+
+
static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
{
write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
@@ -94,6 +135,8 @@ static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctx
write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
write_sysreg_el2(ctxt->gp_regs.regs.pc, elr);
write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
+
+ __sysreg_restore_ap_keys(ctxt);
}
static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
--
1.9.1
Powered by blists - more mailing lists