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From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>,
	"Daniel Henrique Barboza" <dbarboza@ventanamicro.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Michael Tokarev" <mjt@tls.msk.ru>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Marcelo Tosatti" <mtosatti@redhat.com>,
	"Daniel P . Berrangé" <berrange@redhat.com>
Subject: Re: [PATCH v4 0/3] target/i386: Restrict system-specific features from user emulation
Date: Wed, 13 Sep 2023 11:26:23 +0200	[thread overview]
Message-ID: <6cee629b-c1f6-7466-7881-4cc5296f497d@linaro.org> (raw)
In-Reply-To: <CABgObfaz+Tdb6YzwbAeRH=zdXtzVK7VLFv2Lc-MxQMAxbhwnfg@mail.gmail.com>

On 12/9/23 19:25, Paolo Bonzini wrote:

>      > However, the dependency of user-mode emulation on KVM is really an
>      > implementation detail of QEMU.  It's very much baked into
>     linux-user and
>      > hard to remove, but I'm not sure it's a good idea to add more #ifdef
>      > CONFIG_USER_ONLY around KVM code.
> 
>     Do you rather v3 then?
> 
>     https://lore.kernel.org/qemu-devel/20230911142729.25548-1-philmd@linaro.org/ <https://lore.kernel.org/qemu-devel/20230911142729.25548-1-philmd@linaro.org/>
> 
> 
> No, if we want a small patch it is better to replace kvm_enabled() with 
> CONFIG_KVM, and also follow Kevin's suggestion to make it fail at 
> compile time.

For target common code (shared between user/system), CONFIG_KVM is not
a replacement for !CONFIG_USER_ONLY, since it can be always enabled;
which is why we defer to runtime check with kvm_enabled().

> Having stub prototypes was done because we expected the compiler to 
> remove the dead code.
> 
> Paolo



      reply	other threads:[~2023-09-13  9:27 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-11 21:13 [PATCH v4 0/3] target/i386: Restrict system-specific features from user emulation Philippe Mathieu-Daudé
2023-09-11 21:13 ` [PATCH v4 1/3] target/i386: Check kvm_hyperv_expand_features() return value Philippe Mathieu-Daudé
2023-09-11 21:13 ` [RFC PATCH v4 2/3] target/i386: Restrict system-specific features from user emulation Philippe Mathieu-Daudé
2023-09-12 14:05   ` Paolo Bonzini
2023-09-13  9:02     ` Philippe Mathieu-Daudé
2023-09-11 21:13 ` [PATCH v4 3/3] target/i386: Prohibit target specific KVM prototypes on " Philippe Mathieu-Daudé
2023-09-12 14:07 ` [PATCH v4 0/3] target/i386: Restrict system-specific features from " Paolo Bonzini
2023-09-12 16:44   ` Philippe Mathieu-Daudé
2023-09-12 17:25     ` Paolo Bonzini
2023-09-13  9:26       ` Philippe Mathieu-Daudé [this message]

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