From: Marc Zyngier <marc.zyngier@arm.com>
To: Christoffer Dall <christoffer.dall@linaro.org>
Cc: kvm@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 05/21] arm64: KVM: VHE: Turn VTCR_EL2 setup into a reusable macro
Date: Mon, 1 Feb 2016 14:21:57 +0000 [thread overview]
Message-ID: <56AF6A05.5020501@arm.com> (raw)
In-Reply-To: <20160201131300.GH1478@cbox>
On 01/02/16 13:13, Christoffer Dall wrote:
> On Mon, Jan 25, 2016 at 03:53:39PM +0000, Marc Zyngier wrote:
>> On a VHE-capable system, there is no point in setting VTCR_EL2
>> at KVM init time. We can perfectly set it up when the kernel
>> boots, removing the need for a more complicated configuration.
>
> what's the complicated configuration which is avoided?
With VHE, there is no hyp-init at all, so what we avoid is a weird init
sequence where we have to execute part of this hyp-init, but not all of it.
>>
>> In order to allow this, turn VTCR_EL2 setup into a macro that
>> we'll be able to reuse at boot time.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>> arch/arm64/include/asm/kvm_mmu.h | 23 +++++++++++++++++++++++
>> arch/arm64/kvm/hyp-init.S | 18 +-----------------
>> 2 files changed, 24 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
>> index 7364339..d3e6d7b 100644
>> --- a/arch/arm64/include/asm/kvm_mmu.h
>> +++ b/arch/arm64/include/asm/kvm_mmu.h
>> @@ -56,6 +56,29 @@
>>
>> #ifdef __ASSEMBLY__
>>
>> +#include <asm/kvm_arm.h>
>> +
>> +.macro setup_vtcr tmp1, tmp2
>> + mov \tmp1, #(VTCR_EL2_FLAGS & 0xffff)
>> + movk \tmp1, #(VTCR_EL2_FLAGS >> 16), lsl #16
>> + /*
>> + * Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in
>> + * VTCR_EL2.
>> + */
>> + mrs \tmp2, id_aa64mmfr0_el1
>> + bfi \tmp1, \tmp2, #16, #3
>> + /*
>> + * Read the VMIDBits bits from ID_AA64MMFR1_EL1 and set the VS bit in
>> + * VTCR_EL2.
>> + */
>> + mrs \tmp2, ID_AA64MMFR1_EL1
>> + ubfx \tmp2, \tmp2, #5, #1
>> + lsl \tmp2, \tmp2, #VTCR_EL2_VS
>> + orr \tmp1, \tmp1, \tmp2
>> +
>> + msr vtcr_el2, \tmp1
>> + isb
>> +.endm
>
> this feels like an awful lot of code in a header file.
interrupt_head.S respectfully disagrees with you ;-).
> Is it crazy to imagine wanting to have different T0SZ for different VMs
> in the future? In that case, the T0SZ stuff should stay in KVM...
That's a rather compelling argument indeed. I'll see if I can turn the
thing around in a slightly nicer way. How about moving it out of
hyp-init.S altogether, and into C code?
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2016-02-01 14:21 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-25 15:53 [PATCH v2 00/21] arm64: Virtualization Host Extension support Marc Zyngier
2016-01-25 15:53 ` [PATCH v2 01/21] arm/arm64: Add new is_kernel_in_hyp_mode predicate Marc Zyngier
2016-02-01 13:59 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 02/21] arm64: Allow the arch timer to use the HYP timer Marc Zyngier
2016-02-01 12:29 ` Christoffer Dall
2016-02-01 13:42 ` Marc Zyngier
2016-02-01 15:37 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 03/21] arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature Marc Zyngier
2016-02-01 13:59 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 04/21] arm64: KVM: Skip HYP setup when already running in HYP Marc Zyngier
2016-02-01 13:59 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 05/21] arm64: KVM: VHE: Turn VTCR_EL2 setup into a reusable macro Marc Zyngier
2016-02-01 13:13 ` Christoffer Dall
2016-02-01 14:21 ` Marc Zyngier [this message]
2016-02-01 15:38 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 06/21] arm64: KVM: VHE: Patch out use of HVC Marc Zyngier
2016-02-01 13:16 ` Christoffer Dall
2016-02-01 13:34 ` Marc Zyngier
2016-02-01 15:36 ` Catalin Marinas
2016-02-01 16:20 ` Marc Zyngier
2016-02-01 17:08 ` Ard Biesheuvel
2016-02-01 17:28 ` Marc Zyngier
2016-02-02 15:42 ` Christoffer Dall
2016-02-01 15:39 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 07/21] arm64: KVM: VHE: Patch out kern_hyp_va Marc Zyngier
2016-02-01 13:20 ` Christoffer Dall
2016-02-01 13:38 ` Marc Zyngier
2016-02-01 15:40 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 08/21] arm64: KVM: VHE: Introduce unified system register accessors Marc Zyngier
2016-02-01 13:47 ` Christoffer Dall
2016-02-01 14:04 ` Marc Zyngier
2016-02-01 15:43 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 09/21] arm64: KVM: VHE: Differenciate host/guest sysreg save/restore Marc Zyngier
2016-02-01 13:59 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 10/21] arm64: KVM: VHE: Split save/restore of sysregs shared between EL1 and EL2 Marc Zyngier
2016-02-01 13:54 ` Christoffer Dall
2016-02-02 9:46 ` Marc Zyngier
2016-02-02 15:46 ` Christoffer Dall
2016-02-02 16:19 ` Marc Zyngier
2016-02-02 20:07 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 11/21] arm64: KVM: VHE: Use unified system register accessors Marc Zyngier
2016-02-01 13:59 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 12/21] arm64: KVM: VHE: Enable minimal sysreg save/restore Marc Zyngier
2016-02-01 14:02 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 13/21] arm64: KVM: VHE: Make __fpsimd_enabled VHE aware Marc Zyngier
2016-02-01 14:17 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 14/21] arm64: KVM: VHE: Implement VHE activate/deactivate_traps Marc Zyngier
2016-02-01 14:20 ` Christoffer Dall
2016-02-02 11:27 ` Marc Zyngier
2016-01-25 15:53 ` [PATCH v2 15/21] arm64: KVM: VHE: Use unified sysreg accessors for timer Marc Zyngier
2016-02-01 14:23 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 16/21] arm64: KVM: VHE: Add fpsimd enabling on guest access Marc Zyngier
2016-02-01 14:24 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 17/21] arm64: KVM: VHE: Add alternative panic handling Marc Zyngier
2016-02-01 14:26 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 18/21] arm64: KVM: Introduce hyp_alternate_value helper Marc Zyngier
2016-02-01 14:41 ` Christoffer Dall
2016-02-02 13:42 ` Marc Zyngier
2016-02-02 15:47 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 19/21] arm64: KVM: Move most of the fault decoding to C Marc Zyngier
2016-02-01 15:21 ` Christoffer Dall
2016-02-02 14:24 ` Marc Zyngier
2016-02-02 15:50 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 20/21] arm64: VHE: Add support for running Linux in EL2 mode Marc Zyngier
2016-01-26 14:04 ` Suzuki K. Poulose
2016-01-26 14:30 ` Suzuki K. Poulose
2016-02-01 15:26 ` Christoffer Dall
2016-01-25 15:53 ` [PATCH v2 21/21] arm64: Panic when VHE and non VHE CPUs coexist Marc Zyngier
2016-01-26 14:25 ` Suzuki K. Poulose
2016-01-26 14:34 ` Marc Zyngier
2016-02-01 15:36 ` Christoffer Dall
2016-02-02 15:32 ` Marc Zyngier
2016-02-03 8:49 ` Christoffer Dall
2016-02-03 17:45 ` Marc Zyngier
2016-02-03 19:12 ` Christoffer Dall
2016-01-25 16:15 ` [PATCH v2 00/21] arm64: Virtualization Host Extension support Arnd Bergmann
2016-01-25 16:23 ` Marc Zyngier
2016-01-25 16:26 ` Arnd Bergmann
2016-01-25 16:26 ` Will Deacon
2016-01-25 16:37 ` Marc Zyngier
2016-01-25 16:44 ` Will Deacon
2016-01-25 19:16 ` Marc Zyngier
2016-02-01 16:25 ` Christoffer Dall
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