Re: [PATCH v2 05/21] arm64: KVM: VHE: Turn VTCR_EL2 setup into a reusable macro
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From: Christoffer Dall <hidden>
Date: 2016-02-01 13:12:38
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kvmarm, linux-arm-kernel, lkml
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?
quoted hunk ↗ jump to hunk
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 <redacted> --- 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. 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... Thanks, -Christoffer
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/* * Convert a kernel VA into a HYP VA. * reg: VA to be converted.diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index 3e568dc..4143e2c 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S@@ -87,23 +87,7 @@ __do_hyp_init: #endif msr tcr_el2, x4 - ldr x4, =VTCR_EL2_FLAGS - /* - * Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in - * VTCR_EL2. - */ - mrs x5, ID_AA64MMFR0_EL1 - bfi x4, x5, #16, #3 - /* - * Read the VMIDBits bits from ID_AA64MMFR1_EL1 and set the VS bit in - * VTCR_EL2. - */ - mrs x5, ID_AA64MMFR1_EL1 - ubfx x5, x5, #5, #1 - lsl x5, x5, #VTCR_EL2_VS - orr x4, x4, x5 - - msr vtcr_el2, x4 + setup_vtcr x4, x5 mrs x4, mair_el1 msr mair_el2, x4-- 2.1.4