From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Quentin Perret <qperret@google.com>,
Will Deacon <will@kernel.org>, Fuad Tabba <tabba@google.com>
Subject: Re: [PATCH v2 02/17] arm64: Prevent the use of is_kernel_in_hyp_mode() in hypervisor code
Date: Tue, 30 May 2023 19:54:51 +0000 [thread overview]
Message-ID: <ZHZUi/4kXxRmCa7a@linux.dev> (raw)
In-Reply-To: <20230526143348.4072074-3-maz@kernel.org>
Hi Marc,
On Fri, May 26, 2023 at 03:33:33PM +0100, Marc Zyngier wrote:
> Using is_kernel_in_hyp_mode() in hypervisor code is a pretty bad
> mistake. This helper only checks for CurrentEL being EL2, which
> is always true.
>
> Make the link fail if using the helper in hypervisor context
> by referencing a non-existent function. Whilst we're at it,
> flag the helper as __always_inline, which it really should be.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> arch/arm64/include/asm/virt.h | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
> index 4eb601e7de50..91029709d133 100644
> --- a/arch/arm64/include/asm/virt.h
> +++ b/arch/arm64/include/asm/virt.h
> @@ -110,8 +110,13 @@ static inline bool is_hyp_mode_mismatched(void)
> return __boot_cpu_mode[0] != __boot_cpu_mode[1];
> }
>
> -static inline bool is_kernel_in_hyp_mode(void)
> +extern void gotcha_is_kernel_in_hyp_mode(void);
> +
> +static __always_inline bool is_kernel_in_hyp_mode(void)
> {
> +#if defined(__KVM_NVHE_HYPERVISOR__) || defined(__KVM_VHE_HYPERVISOR__)
> + gotcha_is_kernel_in_hyp_mode();
> +#endif
> return read_sysreg(CurrentEL) == CurrentEL_EL2;
> }
Would BUILD_BUG() work in this context, or have I missed something?
--
Thanks,
Oliver
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next prev parent reply other threads:[~2023-05-30 19:55 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-26 14:33 [PATCH v2 00/17] KVM: arm64: Allow using VHE in the nVHE hypervisor Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 01/17] KVM: arm64: Drop is_kernel_in_hyp_mode() from __invalidate_icache_guest_page() Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 02/17] arm64: Prevent the use of is_kernel_in_hyp_mode() in hypervisor code Marc Zyngier
2023-05-30 19:54 ` Oliver Upton [this message]
2023-05-31 7:17 ` Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 03/17] arm64: Turn kaslr_feature_override into a generic SW feature override Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 04/17] arm64: Add KVM_HVHE capability and has_hvhe() predicate Marc Zyngier
2023-06-01 7:06 ` Oliver Upton
2023-06-01 12:27 ` Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 05/17] arm64: Don't enable VHE for the kernel if OVERRIDE_HVHE is set Marc Zyngier
2023-06-01 7:32 ` Oliver Upton
2023-06-01 12:48 ` Marc Zyngier
2023-06-01 20:10 ` Oliver Upton
2023-05-26 14:33 ` [PATCH v2 06/17] arm64: Allow EL1 physical timer access when running VHE Marc Zyngier
2023-06-01 6:34 ` Oliver Upton
2023-06-01 11:59 ` Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 07/17] arm64: Use CPACR_EL1 format to set CPTR_EL2 when E2H is set Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 08/17] KVM: arm64: Remove alternatives from sysreg accessors in VHE hypervisor context Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 09/17] KVM: arm64: Key use of VHE instructions in nVHE code off ARM64_KVM_HVHE Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 10/17] KVM: arm64: Force HCR_EL2.E2H when ARM64_KVM_HVHE is set Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 11/17] KVM: arm64: Disable TTBR1_EL2 when using ARM64_KVM_HVHE Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 12/17] KVM: arm64: Adjust EL2 stage-1 leaf AP bits when ARM64_KVM_HVHE is set Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 13/17] KVM: arm64: Rework CPTR_EL2 programming for HVHE configuration Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 14/17] KVM: arm64: Program the timer traps with VHE layout in hVHE mode Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 15/17] KVM: arm64: Force HCR_E2H in guest context when ARM64_KVM_HVHE is set Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 16/17] arm64: Allow arm64_sw.hvhe on command line Marc Zyngier
2023-05-26 14:33 ` [PATCH v2 17/17] KVM: arm64: Terrible timer hack for M1 with hVHE Marc Zyngier
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