linux-kernel - [PATCH RFC v2 06/22] KVM: arm64: Make FFR restore optional in __sve_restore

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Message-Id: <20231222-kvm-arm64-sme-v2-6-da226cb180bb@kernel.org>
Date: Fri, 22 Dec 2023 16:21:14 +0000
From: Mark Brown <broonie@...nel.org>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
 James Morse <james.morse@....com>, 
 Suzuki K Poulose <suzuki.poulose@....com>, 
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
 Paolo Bonzini <pbonzini@...hat.com>, Jonathan Corbet <corbet@....net>, 
 Shuah Khan <shuah@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, 
 linux-kernel@...r.kernel.org, kvm@...r.kernel.org, 
 linux-doc@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 Mark Brown <broonie@...nel.org>
Subject: [PATCH RFC v2 06/22] KVM: arm64: Make FFR restore optional in
 __sve_restore_state()

Since FFR is an optional feature of SME's streaming SVE mode in order to
support load of guest register state when SME is implemented we need to
provide callers of __sve_restore_state() access to the flag that the
sve_load macro has indicating if FFR should be loaded. Do so, simply a
matter of removing the hard coding in the asm.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 arch/arm64/include/asm/kvm_hyp.h        | 2 +-
 arch/arm64/kvm/hyp/fpsimd.S             | 1 -
 arch/arm64/kvm/hyp/include/hyp/switch.h | 2 +-
 3 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 145ce73fc16c..7ac38ed90062 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -111,7 +111,7 @@ void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu);
 
 void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
 void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
-void __sve_restore_state(void *sve_pffr, u32 *fpsr);
+void __sve_restore_state(void *sve_pffr, u32 *fpsr, bool restore_ffr);
 
 u64 __guest_enter(struct kvm_vcpu *vcpu);
 
diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
index 61e6f3ba7b7d..8940954b5420 100644
--- a/arch/arm64/kvm/hyp/fpsimd.S
+++ b/arch/arm64/kvm/hyp/fpsimd.S
@@ -21,7 +21,6 @@ SYM_FUNC_START(__fpsimd_restore_state)
 SYM_FUNC_END(__fpsimd_restore_state)
 
 SYM_FUNC_START(__sve_restore_state)
-	mov	x2, #1
 	sve_load 0, x1, x2, 3
 	ret
 SYM_FUNC_END(__sve_restore_state)
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index f99d8af0b9af..9601212bd3ce 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -286,7 +286,7 @@ static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
 {
 	sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, SYS_ZCR_EL2);
 	__sve_restore_state(vcpu_sve_pffr(vcpu),
-			    &vcpu->arch.ctxt.fp_regs.fpsr);
+			    &vcpu->arch.ctxt.fp_regs.fpsr, true);
 	write_sysreg_el1(__vcpu_sys_reg(vcpu, ZCR_EL1), SYS_ZCR);
 }
 

-- 
2.30.2