linux-kernel - Re: [PATCH v2 3/5] powerpc: kvm: drop 32-bit booke

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Message-ID: <e7972ba881ed8c0ed8c82379c4e9a2e88cd94ceb.camel@redhat.com>
Date: Mon, 06 Jan 2025 19:53:11 -0500
From: Crystal Wood <crwood@...hat.com>
To: Arnd Bergmann <arnd@...nel.org>, kvm@...r.kernel.org
Cc: Arnd Bergmann <arnd@...db.de>, Thomas Bogendoerfer
 <tsbogend@...ha.franken.de>, Huacai Chen <chenhuacai@...nel.org>, Jiaxun
 Yang <jiaxun.yang@...goat.com>, Michael Ellerman <mpe@...erman.id.au>,
 Nicholas Piggin <npiggin@...il.com>, Christophe Leroy
 <christophe.leroy@...roup.eu>, Naveen N Rao <naveen@...nel.org>, Madhavan
 Srinivasan <maddy@...ux.ibm.com>, Alexander Graf <graf@...zon.com>, Anup
 Patel <anup@...infault.org>, Atish Patra <atishp@...shpatra.org>, Paul
 Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>,
 Albert Ou <aou@...s.berkeley.edu>, Sean Christopherson <seanjc@...gle.com>,
 Paolo Bonzini <pbonzini@...hat.com>, Thomas Gleixner <tglx@...utronix.de>,
 Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Dave Hansen
 <dave.hansen@...ux.intel.com>, x86@...nel.org, "H. Peter Anvin"
 <hpa@...or.com>, Vitaly Kuznetsov <vkuznets@...hat.com>, David Woodhouse
 <dwmw2@...radead.org>, Paul Durrant <paul@....org>, Marc Zyngier
 <maz@...nel.org>,  "A. Wilcox" <AWilcox@...cox-Tech.com>,
 linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org, 
 linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org, 
 linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v2 3/5] powerpc: kvm: drop 32-bit booke

On Sat, 2024-12-21 at 22:42 +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> KVM on PowerPC BookE was introduced in 2008 and supported IBM 44x,
> Freescale e500v2 (32-bit mpc85xx, QuorIQ P1/P2), e500mc (32bit QorIQ
> P2/P3/P4), e5500 (64-bit QorIQ P5/T1) and e6500 (64-bit QorIQ T2/T4).
> 
> Support for 44x was dropped in 2014 as it was seeing very little use,
> but e500v2 and e500mc are still supported as most of the code is shared
> with the 64-bit e5500/e6500 implementation.
> 
> The last of those 32-bit chips were introduced in 2010 but not widely
> adopted when the following 64-bit PowerPC and Arm variants ended up
> being more successful.
> 
> The 64-bit e5500/e6500 are still known to be used with KVM, but I could
> not find any evidence of continued use of the 32-bit ones, so drop
> discontinue those in order to simplify the implementation.
> The changes are purely mechanical, dropping all #ifdef checks for
> CONFIG_64BIT, CONFIG_KVM_E500V2, CONFIG_KVM_E500MC, CONFIG_KVM_BOOKE_HV,
> CONFIG_PPC_85xx, CONFIG_PPC_FPU, CONFIG_SPE and CONFIG_SPE_POSSIBLE,
> which are all known on e5500/e6500.
> 
> Support for 64-bit hosts remains unchanged, for both 32-bit and
> 64-bit guests.
> 
> Link: https://lore.kernel.org/lkml/Z1B1phcpbiYWLgCD@google.com/
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  arch/powerpc/include/asm/kvm_book3s_32.h    |  36 --
>  arch/powerpc/include/asm/kvm_booke.h        |   4 -
>  arch/powerpc/include/asm/kvm_booke_hv_asm.h |   2 -
>  arch/powerpc/kernel/head_85xx.S             |  14 -
>  arch/powerpc/kernel/head_booke.h            |  39 --
>  arch/powerpc/kvm/Kconfig                    |  22 +-
>  arch/powerpc/kvm/Makefile                   |  15 -
>  arch/powerpc/kvm/book3s_32_mmu_host.c       | 396 --------------

Why are book3s files removed by this patch?

> @@ -228,23 +176,16 @@ static inline void kvmppc_save_guest_altivec(struct kvm_vcpu *vcpu)
>  static void kvmppc_vcpu_sync_debug(struct kvm_vcpu *vcpu)
>  {
>  	/* Synchronize guest's desire to get debug interrupts into shadow MSR */
> -#ifndef CONFIG_KVM_BOOKE_HV
>  	vcpu->arch.shadow_msr &= ~MSR_DE;
>  	vcpu->arch.shadow_msr |= vcpu->arch.shared->msr & MSR_DE;
> -#endif

This is an ifndef... the contents should be removed.

-Crystal