From: Marc Zyngier <marc.zyngier@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Christoffer Dall <christoffer.dall@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
kvmarm@lists.cs.columbia.edu
Subject: [PATCH v3 07/23] arm64: KVM: VHE: Patch out use of HVC
Date: Wed, 3 Feb 2016 18:00:00 +0000 [thread overview]
Message-ID: <1454522416-6874-8-git-send-email-marc.zyngier@arm.com> (raw)
In-Reply-To: <1454522416-6874-1-git-send-email-marc.zyngier@arm.com>
With VHE, the host never issues an HVC instruction to get into the
KVM code, as we can simply branch there.
Use runtime code patching to simplify things a bit.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/hyp.S | 7 +++++++
arch/arm64/kvm/hyp/hyp-entry.S | 40 +++++++++++++++++++++++++++++++---------
2 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 0ccdcbb..0689a74 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -17,7 +17,9 @@
#include <linux/linkage.h>
+#include <asm/alternative.h>
#include <asm/assembler.h>
+#include <asm/cpufeature.h>
/*
* u64 kvm_call_hyp(void *hypfn, ...);
@@ -38,6 +40,11 @@
* arch/arm64/kernel/hyp_stub.S.
*/
ENTRY(kvm_call_hyp)
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
hvc #0
ret
+alternative_else
+ b __vhe_hyp_call
+ nop
+alternative_endif
ENDPROC(kvm_call_hyp)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 93e8d983..1bdeee7 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -38,6 +38,34 @@
ldp x0, x1, [sp], #16
.endm
+.macro do_el2_call
+ /*
+ * Shuffle the parameters before calling the function
+ * pointed to in x0. Assumes parameters in x[1,2,3].
+ */
+ sub sp, sp, #16
+ str lr, [sp]
+ mov lr, x0
+ mov x0, x1
+ mov x1, x2
+ mov x2, x3
+ blr lr
+ ldr lr, [sp]
+ add sp, sp, #16
+.endm
+
+ENTRY(__vhe_hyp_call)
+ do_el2_call
+ /*
+ * We used to rely on having an exception return to get
+ * an implicit isb. In the E2H case, we don't have it anymore.
+ * rather than changing all the leaf functions, just do it here
+ * before returning to the rest of the kernel.
+ */
+ isb
+ ret
+ENDPROC(__vhe_hyp_call)
+
el1_sync: // Guest trapped into EL2
save_x0_to_x3
@@ -58,19 +86,13 @@ el1_sync: // Guest trapped into EL2
mrs x0, vbar_el2
b 2f
-1: stp lr, xzr, [sp, #-16]!
-
+1:
/*
- * Compute the function address in EL2, and shuffle the parameters.
+ * Perform the EL2 call
*/
kern_hyp_va x0
- mov lr, x0
- mov x0, x1
- mov x1, x2
- mov x2, x3
- blr lr
+ do_el2_call
- ldp lr, xzr, [sp], #16
2: eret
el1_trap:
--
2.1.4
next prev parent reply other threads:[~2016-02-03 18:00 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 17:59 [PATCH v3 00/23] arm64: Virtualization Host Extension support Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 01/23] arm/arm64: KVM: Add hook for C-based stage2 init Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 02/23] arm64: KVM: Switch to " Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 03/23] arm/arm64: Add new is_kernel_in_hyp_mode predicate Marc Zyngier
2016-02-08 14:41 ` Catalin Marinas
2016-02-03 17:59 ` [PATCH v3 04/23] arm64: Allow the arch timer to use the HYP timer Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 05/23] arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature Marc Zyngier
2016-02-08 14:42 ` Catalin Marinas
2016-02-03 17:59 ` [PATCH v3 06/23] arm64: KVM: Skip HYP setup when already running in HYP Marc Zyngier
2016-02-03 18:00 ` Marc Zyngier [this message]
2016-02-03 18:00 ` [PATCH v3 08/23] arm64: KVM: VHE: Patch out kern_hyp_va Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 09/23] arm64: KVM: VHE: Introduce unified system register accessors Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 10/23] arm64: KVM: VHE: Differenciate host/guest sysreg save/restore Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 11/23] arm64: KVM: VHE: Split save/restore of registers shared between guest and host Marc Zyngier
2016-02-04 19:15 ` Christoffer Dall
2016-02-03 18:00 ` [PATCH v3 12/23] arm64: KVM: VHE: Use unified system register accessors Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 13/23] arm64: KVM: VHE: Enable minimal sysreg save/restore Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 14/23] arm64: KVM: VHE: Make __fpsimd_enabled VHE aware Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 15/23] arm64: KVM: VHE: Implement VHE activate/deactivate_traps Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 16/23] arm64: KVM: VHE: Use unified sysreg accessors for timer Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 17/23] arm64: KVM: VHE: Add fpsimd enabling on guest access Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 18/23] arm64: KVM: VHE: Add alternative panic handling Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 19/23] arm64: KVM: Move most of the fault decoding to C Marc Zyngier
2016-02-04 19:20 ` Christoffer Dall
2016-02-08 14:44 ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 20/23] arm64: perf: Count EL2 events if the kernel is running in HYP Marc Zyngier
2016-02-04 19:23 ` Christoffer Dall
2016-02-05 9:02 ` Marc Zyngier
2016-02-08 14:48 ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if " Marc Zyngier
2016-02-08 15:56 ` Catalin Marinas
2016-02-08 16:45 ` Marc Zyngier
2016-02-08 16:52 ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 22/23] arm64: VHE: Add support for running Linux in EL2 mode Marc Zyngier
2016-02-04 19:25 ` Christoffer Dall
2016-02-08 15:58 ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 23/23] arm64: Panic when VHE and non VHE CPUs coexist Marc Zyngier
2016-02-04 19:25 ` Christoffer Dall
2016-02-08 16:04 ` Catalin Marinas
2016-02-08 16:24 ` Mark Rutland
2016-02-09 12:02 ` Catalin Marinas
2016-02-04 19:26 ` [PATCH v3 00/23] arm64: Virtualization Host Extension support Christoffer Dall
2016-02-05 8:56 ` Marc Zyngier
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