From: james.morse@arm•com (James Morse)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 01/11] KVM: arm64: Store vcpu on the stack during __guest_enter()
Date: Tue, 08 Aug 2017 17:48:29 +0100 [thread overview]
Message-ID: <5989EB5D.6@arm.com> (raw)
In-Reply-To: <20170606195951.GN9464@cbox>
Hi Christoffer,
On 06/06/17 20:59, Christoffer Dall wrote:
> On Mon, May 15, 2017 at 06:43:49PM +0100, James Morse wrote:
>> 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.
>>
>> __guest_enter() stores the host_ctxt on the stack, do the same with
>> the vcpu.
>> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
>> index 12ee62d6d410..113735df7d01 100644
>> --- a/arch/arm64/kvm/hyp/entry.S
>> +++ b/arch/arm64/kvm/hyp/entry.S
>> @@ -159,9 +159,15 @@ 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]!
>>
>> + mov x3, x1
>> +
>
> nit: can you avoid this by using x1 for the vcpu pointer in this routine
> instead?
Unfortunately x1 is clobbered by the __fpsimd_{save,restore}_state() macros that
are called further down this function.
(its a bit obscure:
> fpsimd_save x0, 1
that '1' is used to generate 'x1' or 'w1' in includes/asm/fpsimdmacros.h)
Thanks,
James
next prev parent reply other threads:[~2017-08-08 16:48 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-15 17:43 [PATCH 00/11] arm64/firmware: Software Delegated Exception Interface James Morse
2017-05-15 17:43 ` [PATCH 01/11] KVM: arm64: Store vcpu on the stack during __guest_enter() James Morse
2017-06-06 19:59 ` Christoffer Dall
2017-08-08 16:48 ` James Morse [this message]
2017-08-09 8:48 ` Christoffer Dall
2017-05-15 17:43 ` [PATCH 02/11] KVM: arm/arm64: Convert kvm_host_cpu_state to a static per-cpu allocation James Morse
2017-06-06 19:59 ` Christoffer Dall
2017-05-15 17:43 ` [PATCH 03/11] KVM: arm64: Change hyp_panic()s dependency on tpidr_el2 James Morse
2017-06-06 19:45 ` Christoffer Dall
2017-06-08 10:23 ` James Morse
2017-06-08 10:34 ` Christoffer Dall
2017-05-15 17:43 ` [PATCH 04/11] arm64: alternatives: use tpidr_el2 on VHE hosts James Morse
2017-05-15 17:43 ` [PATCH 05/11] arm64: KVM: Stop save/restoring host tpidr_el1 on VHE James Morse
2017-06-06 20:00 ` Christoffer Dall
2017-05-15 17:43 ` [PATCH 06/11] dt-bindings: add devicetree binding for describing arm64 SDEI firmware James Morse
2017-05-19 1:48 ` Rob Herring
2017-06-07 8:28 ` James Morse
2017-05-15 17:43 ` [PATCH 07/11] firmware: arm_sdei: Add driver for Software Delegated Exceptions James Morse
2017-07-19 13:52 ` Dave Martin
2017-08-08 16:48 ` James Morse
2017-05-15 17:43 ` [PATCH 08/11] arm64: kernel: Add arch-specific SDEI entry code and CPU masking James Morse
2017-05-15 17:43 ` [PATCH 09/11] firmware: arm_sdei: Add support for CPU and system power states James Morse
2017-05-15 17:43 ` [PATCH 10/11] firmware: arm_sdei: add support for CPU private events James Morse
2017-05-15 17:43 ` [PATCH 11/11] KVM: arm64: Delegate support for SDEI to userspace James Morse
2017-06-06 19:58 ` Christoffer Dall
2017-07-26 17:00 ` James Morse
2017-07-27 7:49 ` Christoffer Dall
2017-06-06 19:59 ` [PATCH 00/11] arm64/firmware: Software Delegated Exception Interface Christoffer Dall
2017-06-07 9:45 ` James Morse
2017-06-07 9:53 ` Christoffer Dall
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