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From: Dave Martin <Dave.Martin@arm.com>
To: linux-kernel@vger.kernel.org
Cc: "Andrew Jones" <drjones@redhat.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Eugene Syromiatnikov" <esyr@redhat.com>,
	"Florian Weimer" <fweimer@redhat.com>,
	"H.J. Lu" <hjl.tools@gmail.com>, "Jann Horn" <jannh@google.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Kristina Martšenko" <kristina.martsenko@arm.com>,
	"Marc Zyngier" <maz@kernel.org>,
	"Mark Brown" <broonie@kernel.org>,
	"Paul Elliott" <paul.elliott@arm.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Sudakshina Das" <sudi.das@arm.com>,
	"Szabolcs Nagy" <szabolcs.nagy@arm.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Will Deacon" <will@kernel.org>,
	"Yu-cheng Yu" <yu-cheng.yu@intel.com>,
	"Amit Kachhap" <amit.kachhap@arm.com>,
	"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
	linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 12/12] KVM: arm64: BTI: Reset BTYPE when skipping emulated instructions
Date: Fri, 18 Oct 2019 18:25:45 +0100	[thread overview]
Message-ID: <1571419545-20401-13-git-send-email-Dave.Martin@arm.com> (raw)
In-Reply-To: <1571419545-20401-1-git-send-email-Dave.Martin@arm.com>

Since normal execution of any non-branch instruction resets the
PSTATE BTYPE field to 0, so do the same thing when emulating a
trapped instruction.

Branches don't trap directly, so we should never need to assign a
non-zero value to BTYPE here.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>

---

Changes since v2:

 * Drop (u64) case when masking out PSR_BTYPE_MASK in
   arm64_skip_faulting_instruction().

   PSTATE may grow, but we should address this more generally rather
   than with point hacks.

 * Add { } around if () clause that was unbalanced by the previous
   patch.
---
 arch/arm64/include/asm/kvm_emulate.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index d69c1ef..f41bfdee 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -450,10 +450,12 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
 
 static inline void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr)
 {
-	if (vcpu_mode_is_32bit(vcpu))
+	if (vcpu_mode_is_32bit(vcpu)) {
 		kvm_skip_instr32(vcpu, is_wide_instr);
-	else
+	} else {
 		*vcpu_pc(vcpu) += 4;
+		*vcpu_cpsr(vcpu) &= ~PSR_BTYPE_MASK;
+	}
 
 	/* advance the singlestep state machine */
 	*vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS;
-- 
2.1.4


      parent reply	other threads:[~2019-10-18 17:27 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-18 17:25 [PATCH v3 00/12] arm64: ARMv8.5-A: Branch Target Identification support Dave Martin
2019-10-18 17:25 ` [PATCH v3 01/12] ELF: UAPI and Kconfig additions for ELF program properties Dave Martin
2019-10-29 23:07   ` Kees Cook
2019-10-18 17:25 ` [PATCH v3 02/12] ELF: Add ELF program property parsing support Dave Martin
2019-10-29 23:14   ` Kees Cook
2019-12-11 13:58     ` Mark Brown
2019-10-18 17:25 ` [PATCH v3 03/12] mm: Reserve asm-generic prot flag 0x10 for arch use Dave Martin
2019-10-18 17:25 ` [PATCH v3 04/12] arm64: docs: cpu-feature-registers: Document ID_AA64PFR1_EL1 Dave Martin
2019-10-18 17:25 ` [PATCH v3 05/12] arm64: Basic Branch Target Identification support Dave Martin
2019-10-18 17:25 ` [PATCH v3 06/12] elf: Allow arch to tweak initial mmap prot flags Dave Martin
2019-10-29 23:19   ` Kees Cook
2019-10-18 17:25 ` [PATCH v3 07/12] arm64: elf: Enable BTI at exec based on ELF program properties Dave Martin
2019-10-18 17:25 ` [PATCH v3 08/12] arm64: BTI: Decode BYTPE bits when printing PSTATE Dave Martin
2019-10-18 17:25 ` [PATCH v3 09/12] arm64: traps: Fix inconsistent faulting instruction skipping Dave Martin
2019-10-18 17:25 ` [PATCH v3 10/12] arm64: traps: Shuffle code to eliminate forward declarations Dave Martin
2019-10-18 17:25 ` [PATCH v3 11/12] arm64: BTI: Reset BTYPE when skipping emulated instructions Dave Martin
2019-10-18 17:25 ` Dave Martin [this message]

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