From: james.morse@arm.com (James Morse)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 01/13] KVM: arm64: Store vcpu on the stack during __guest_enter()
Date: Tue, 17 Oct 2017 18:44:20 +0100 [thread overview]
Message-ID: <20171017174432.1684-2-james.morse@arm.com> (raw)
In-Reply-To: <20171017174432.1684-1-james.morse@arm.com>
KVM uses tpidr_el2 as its private vcpu register, which makes sense for
non-vhe world switch as only KVM can access this register. This means
vhe Linux has to use tpidr_el1, which KVM has to save/restore as part
of the host context.
If the SDEI handler code runs behind KVMs back, it mustn't access any
per-cpu variables. To allow this on systems with vhe we need to make
the host use tpidr_el2, saving KVM from save/restoring it.
__guest_enter() stores the host_ctxt on the stack, do the same with
the vcpu.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
---
Changes since v2:
* Added middle paragraph of commit message.
arch/arm64/kvm/hyp/entry.S | 10 +++++++---
arch/arm64/kvm/hyp/hyp-entry.S | 6 +++---
2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 12ee62d6d410..9a8ab5dddd9e 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -62,8 +62,8 @@ ENTRY(__guest_enter)
// Store the host regs
save_callee_saved_regs x1
- // Store the host_ctxt for use at exit time
- str x1, [sp, #-16]!
+ // Store host_ctxt and vcpu for use at exit time
+ stp x1, x0, [sp, #-16]!
add x18, x0, #VCPU_CONTEXT
@@ -159,6 +159,10 @@ abort_guest_exit_end:
ENDPROC(__guest_exit)
ENTRY(__fpsimd_guest_restore)
+ // x0: esr
+ // x1: vcpu
+ // x2-x29,lr: vcpu regs
+ // vcpu x0-x1 on the stack
stp x2, x3, [sp, #-16]!
stp x4, lr, [sp, #-16]!
@@ -173,7 +177,7 @@ alternative_else
alternative_endif
isb
- mrs x3, tpidr_el2
+ mov x3, x1
ldr x0, [x3, #VCPU_HOST_CONTEXT]
kern_hyp_va x0
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 5170ce1021da..fce7cc507e0a 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -104,6 +104,7 @@ el1_trap:
/*
* x0: ESR_EC
*/
+ ldr x1, [sp, #16 + 8] // vcpu stored by __guest_enter
/*
* We trap the first access to the FP/SIMD to save the host context
@@ -116,19 +117,18 @@ alternative_if_not ARM64_HAS_NO_FPSIMD
b.eq __fpsimd_guest_restore
alternative_else_nop_endif
- mrs x1, tpidr_el2
mov x0, #ARM_EXCEPTION_TRAP
b __guest_exit
el1_irq:
stp x0, x1, [sp, #-16]!
- mrs x1, tpidr_el2
+ ldr x1, [sp, #16 + 8]
mov x0, #ARM_EXCEPTION_IRQ
b __guest_exit
el1_error:
stp x0, x1, [sp, #-16]!
- mrs x1, tpidr_el2
+ ldr x1, [sp, #16 + 8]
mov x0, #ARM_EXCEPTION_EL1_SERROR
b __guest_exit
--
2.13.3
next prev parent reply other threads:[~2017-10-17 17:44 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-17 17:44 [PATCH v4 00/13] arm64/firmware: Software Delegated Exception Interface James Morse
2017-10-17 17:44 ` James Morse [this message]
2017-10-17 17:44 ` [PATCH v4 02/13] KVM: arm/arm64: Convert kvm_host_cpu_state to a static per-cpu allocation James Morse
2017-10-17 17:44 ` [PATCH v4 03/13] KVM: arm64: Change hyp_panic()s dependency on tpidr_el2 James Morse
2017-10-17 17:44 ` [PATCH v4 04/13] arm64: alternatives: use tpidr_el2 on VHE hosts James Morse
2017-10-18 11:00 ` Catalin Marinas
2017-10-17 17:44 ` [PATCH v4 05/13] KVM: arm64: Stop save/restoring host tpidr_el1 on VHE James Morse
2017-10-17 17:44 ` [PATCH v4 06/13] Docs: dt: add devicetree binding for describing arm64 SDEI firmware James Morse
2017-10-17 17:44 ` [PATCH v4 07/13] firmware: arm_sdei: Add driver for Software Delegated Exceptions James Morse
2017-10-18 11:09 ` Catalin Marinas
2017-10-17 17:44 ` [PATCH v4 08/13] arm64: Add vmap_stack header file James Morse
2017-10-18 11:10 ` Catalin Marinas
2017-10-17 17:44 ` [PATCH v4 09/13] arm64: kernel: Add arch-specific SDEI entry code and CPU masking James Morse
2017-10-18 11:18 ` Catalin Marinas
2017-10-17 17:44 ` [PATCH v4 10/13] firmware: arm_sdei: Add support for CPU and system power states James Morse
2017-10-18 11:11 ` Catalin Marinas
2017-10-18 17:17 ` Will Deacon
2017-10-24 17:34 ` James Morse
2017-10-25 14:43 ` Will Deacon
2017-10-17 17:44 ` [PATCH v4 11/13] firmware: arm_sdei: add support for CPU private events James Morse
2017-10-18 11:11 ` Catalin Marinas
2017-10-18 17:19 ` Will Deacon
2017-10-24 17:34 ` James Morse
2017-11-01 15:59 ` James Morse
2017-10-17 17:44 ` [PATCH v4 12/13] arm64: acpi: Remove __init from acpi_psci_use_hvc() for use by SDEI James Morse
2017-10-18 11:11 ` Catalin Marinas
2017-10-17 17:44 ` [PATCH v4 13/13] firmware: arm_sdei: Discover SDEI support via ACPI James Morse
2017-10-18 11:12 ` Catalin Marinas
2017-10-18 17:16 ` [PATCH v4 00/13] arm64/firmware: Software Delegated Exception Interface Will Deacon
2017-10-30 15:58 ` [PATCH v4 14/13] firmware: arm_sdei: Move cpuhotplug registration later James Morse
2017-11-01 15:59 ` [PATCH 15/13] firmware: arm_sdei: move the frozen flag under the spinlock James Morse
2017-11-08 15:11 ` James Morse
2017-11-08 16:06 ` [PATCH v4 15/13] firmware: arm_sdei: be more robust against cpu-hotplug James Morse
2017-11-13 11:01 ` Will Deacon
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