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From: Marc Zyngier <maz@kernel.org>
To: Elliot Berman <quic_eberman@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] KVM: arm64: Only set KVM_MODE_PROTECTED if is_hyp_mode_available()
Date: Sat, 10 Sep 2022 10:09:31 +0100	[thread overview]
Message-ID: <878rmrr3xw.wl-maz@kernel.org> (raw)
In-Reply-To: <05057e2a-1a85-69ba-ffcd-584d4090467a@quicinc.com>

On Fri, 09 Sep 2022 18:55:18 +0100,
Elliot Berman <quic_eberman@quicinc.com> wrote:
> 
> 
> 
> On 9/9/2022 10:28 AM, Catalin Marinas wrote:
> > On Fri, Sep 09, 2022 at 07:45:52AM -0700, Elliot Berman wrote:
> >> Do not switch kvm_mode to KVM_MODE_PROTECTED if hypervisor mode is not
> >> available. This prevents "Protected KVM" cpu capability being reported
> >> when Linux is booting in EL1 and would not have KVM enabled.
> >> 
> >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> >> ---
> >>   arch/arm64/kvm/arm.c | 4 +++-
> >>   1 file changed, 3 insertions(+), 1 deletion(-)
> >> 
> >> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> >> index 8fe73ee5fa84..861f4b388879 100644
> >> --- a/arch/arm64/kvm/arm.c
> >> +++ b/arch/arm64/kvm/arm.c
> >> @@ -2272,7 +2272,9 @@ static int __init early_kvm_mode_cfg(char *arg)
> >>   		return -EINVAL;
> >>     	if (strcmp(arg, "protected") == 0) {
> >> -		if (!is_kernel_in_hyp_mode())
> >> +		if (!is_hyp_mode_available())
> >> +			kvm_mode = KVM_MODE_DEFAULT;
> > 
> > I think kvm_mode is already KVM_MODE_DEFAULT at this point. You may want
> > to print a warning instead.
> > 
> 
> Does it make sense to print warning for kvm-arm.mode=nvhe as well?

In general, specifying a kvm-arm.mode when no hypervisor mode is
available should be reported as a warning.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Elliot Berman <quic_eberman@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	"Suzuki K\ Poulose" <suzuki.poulose@arm.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <kvmarm@lists.cs.columbia.edu>
Subject: Re: [PATCH v2] KVM: arm64: Only set KVM_MODE_PROTECTED if is_hyp_mode_available()
Date: Sat, 10 Sep 2022 10:09:31 +0100	[thread overview]
Message-ID: <878rmrr3xw.wl-maz@kernel.org> (raw)
In-Reply-To: <05057e2a-1a85-69ba-ffcd-584d4090467a@quicinc.com>

On Fri, 09 Sep 2022 18:55:18 +0100,
Elliot Berman <quic_eberman@quicinc.com> wrote:
> 
> 
> 
> On 9/9/2022 10:28 AM, Catalin Marinas wrote:
> > On Fri, Sep 09, 2022 at 07:45:52AM -0700, Elliot Berman wrote:
> >> Do not switch kvm_mode to KVM_MODE_PROTECTED if hypervisor mode is not
> >> available. This prevents "Protected KVM" cpu capability being reported
> >> when Linux is booting in EL1 and would not have KVM enabled.
> >> 
> >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> >> ---
> >>   arch/arm64/kvm/arm.c | 4 +++-
> >>   1 file changed, 3 insertions(+), 1 deletion(-)
> >> 
> >> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> >> index 8fe73ee5fa84..861f4b388879 100644
> >> --- a/arch/arm64/kvm/arm.c
> >> +++ b/arch/arm64/kvm/arm.c
> >> @@ -2272,7 +2272,9 @@ static int __init early_kvm_mode_cfg(char *arg)
> >>   		return -EINVAL;
> >>     	if (strcmp(arg, "protected") == 0) {
> >> -		if (!is_kernel_in_hyp_mode())
> >> +		if (!is_hyp_mode_available())
> >> +			kvm_mode = KVM_MODE_DEFAULT;
> > 
> > I think kvm_mode is already KVM_MODE_DEFAULT at this point. You may want
> > to print a warning instead.
> > 
> 
> Does it make sense to print warning for kvm-arm.mode=nvhe as well?

In general, specifying a kvm-arm.mode when no hypervisor mode is
available should be reported as a warning.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-09-10  9:09 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-09 14:45 [PATCH v2] KVM: arm64: Only set KVM_MODE_PROTECTED if is_hyp_mode_available() Elliot Berman
2022-09-09 14:45 ` Elliot Berman
2022-09-09 14:45 ` Elliot Berman
2022-09-09 17:28 ` Catalin Marinas
2022-09-09 17:28   ` Catalin Marinas
2022-09-09 17:28   ` Catalin Marinas
2022-09-09 17:55   ` Elliot Berman
2022-09-09 17:55     ` Elliot Berman
2022-09-09 17:55     ` Elliot Berman
2022-09-10  9:09     ` Marc Zyngier [this message]
2022-09-10  9:09       ` Marc Zyngier
2022-09-10 13:43       ` Will Deacon
2022-09-10 13:43         ` Will Deacon
2022-09-10 13:43         ` Will Deacon
2022-09-10 14:20         ` Marc Zyngier
2022-09-10 14:20           ` Marc Zyngier
2022-09-10 14:20           ` Marc Zyngier

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