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From: David Long <dave.long@linaro.org>
To: <stable@vger.kernel.org>,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Tony Lindgren <tony@atomide.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Mark Rutland <mark.rutland@arm.com>
Cc: Greg KH <gregkh@linuxfoundation.org>, Mark Brown <broonie@kernel.org>
Subject: [PATCH 4.14 14/24] ARM: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
Date: Mon, 15 Oct 2018 11:32:08 -0400	[thread overview]
Message-ID: <1539617538-22328-15-git-send-email-dave.long@linaro.org> (raw)
In-Reply-To: <1539617538-22328-1-git-send-email-dave.long@linaro.org>

From: Russell King <rmk+kernel@armlinux.org.uk>

Commit b800acfc70d9fb81fbd6df70f2cf5e20f70023d0 upstream.

We want SMCCC_ARCH_WORKAROUND_1 to be fast. As fast as possible.
So let's intercept it as early as we can by testing for the
function call number as soon as we've identified a HVC call
coming from the guest.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
---
 arch/arm/kvm/hyp/hyp-entry.S | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 918a05d..aa3f9a9 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -16,6 +16,7 @@
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
+#include <linux/arm-smccc.h>
 #include <linux/linkage.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_asm.h>
@@ -202,7 +203,7 @@ hyp_hvc:
 	lsr     r2, r2, #16
 	and     r2, r2, #0xff
 	cmp     r2, #0
-	bne	guest_trap		@ Guest called HVC
+	bne	guest_hvc_trap		@ Guest called HVC
 
 	/*
 	 * Getting here means host called HVC, we shift parameters and branch
@@ -253,6 +254,20 @@ THUMB(	orr	lr, #1)
 	pop	{r2, lr}
 	eret
 
+guest_hvc_trap:
+	movw	r2, #:lower16:ARM_SMCCC_ARCH_WORKAROUND_1
+	movt	r2, #:upper16:ARM_SMCCC_ARCH_WORKAROUND_1
+	ldr	r0, [sp]		@ Guest's r0
+	teq	r0, r2
+	bne	guest_trap
+	add	sp, sp, #12
+	@ Returns:
+	@ r0 = 0
+	@ r1 = HSR value (perfectly predictable)
+	@ r2 = ARM_SMCCC_ARCH_WORKAROUND_1
+	mov	r0, #0
+	eret
+
 guest_trap:
 	load_vcpu r0			@ Load VCPU pointer to r0
 
-- 
2.5.0

  parent reply	other threads:[~2018-10-15 23:18 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-15 15:31 [PATCH 4.14 00/24] V4.14 backport of 32-bit arm spectre patches David Long
2018-10-15 15:31 ` [PATCH 4.14 01/24] ARM: add more CPU part numbers for Cortex and Brahma B15 CPUs David Long
2018-10-15 15:31 ` [PATCH 4.14 02/24] ARM: bugs: prepare processor bug infrastructure David Long
2018-10-15 15:31 ` [PATCH 4.14 03/24] ARM: bugs: hook processor bug checking into SMP and suspend paths David Long
2018-10-15 15:31 ` [PATCH 4.14 04/24] ARM: bugs: add support for per-processor bug checking David Long
2018-10-15 15:31 ` [PATCH 4.14 05/24] ARM: spectre: add Kconfig symbol for CPUs vulnerable to Spectre David Long
2018-10-15 15:32 ` [PATCH 4.14 06/24] ARM: spectre-v2: harden branch predictor on context switches David Long
2018-10-15 15:32 ` [PATCH 4.14 07/24] ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit David Long
2018-10-15 15:32 ` [PATCH 4.14 08/24] ARM: spectre-v2: harden user aborts in kernel space David Long
2018-10-15 15:32 ` [PATCH 4.14 09/24] ARM: spectre-v2: add firmware based hardening David Long
2018-10-15 15:32 ` [PATCH 4.14 10/24] ARM: spectre-v2: warn about incorrect context switching functions David Long
2018-10-15 15:32 ` [PATCH 4.14 11/24] ARM: KVM: invalidate BTB on guest exit for Cortex-A12/A17 David Long
2018-10-15 15:32 ` [PATCH 4.14 12/24] ARM: KVM: invalidate icache on guest exit for Cortex-A15 David Long
2018-10-15 15:32 ` [PATCH 4.14 13/24] ARM: spectre-v2: KVM: invalidate icache on guest exit for Brahma B15 David Long
2018-10-15 15:32 ` David Long [this message]
2018-10-15 15:32 ` [PATCH 4.14 15/24] ARM: KVM: report support for SMCCC_ARCH_WORKAROUND_1 David Long
2018-10-15 15:32 ` [PATCH 4.14 16/24] ARM: spectre-v1: add speculation barrier (csdb) macros David Long
2018-10-15 15:32 ` [PATCH 4.14 17/24] ARM: spectre-v1: add array_index_mask_nospec() implementation David Long
2018-10-15 15:32 ` [PATCH 4.14 18/24] ARM: spectre-v1: fix syscall entry David Long
2018-10-15 15:32 ` [PATCH 4.14 19/24] ARM: signal: copy registers using __copy_from_user() David Long
2018-10-15 15:32 ` [PATCH 4.14 20/24] ARM: vfp: use __copy_from_user() when restoring VFP state David Long
2018-10-15 15:32 ` [PATCH 4.14 21/24] ARM: oabi-compat: copy semops using __copy_from_user() David Long
2018-10-15 15:32 ` [PATCH 4.14 22/24] ARM: use __inttype() in get_user() David Long
2018-10-15 15:32 ` [PATCH 4.14 23/24] ARM: spectre-v1: use get_user() for __get_user() David Long
2018-10-15 15:32 ` [PATCH 4.14 24/24] ARM: spectre-v1: mitigate user accesses David Long
2018-10-16 16:10 ` [PATCH 4.14 00/24] V4.14 backport of 32-bit arm spectre patches Greg KH

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