linux-kernel - [PATCH v5 19/28] KVM: arm64: Provide assembly for SME register access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250417-kvm-arm64-sme-v5-19-f469a2d5f574@kernel.org>
Date: Thu, 17 Apr 2025 01:25:23 +0100
From: Mark Brown <broonie@...nel.org>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
 Joey Gouly <joey.gouly@....com>, Catalin Marinas <catalin.marinas@....com>, 
 Suzuki K Poulose <suzuki.poulose@....com>, Will Deacon <will@...nel.org>, 
 Paolo Bonzini <pbonzini@...hat.com>, Jonathan Corbet <corbet@....net>, 
 Shuah Khan <shuah@...nel.org>
Cc: Dave Martin <Dave.Martin@....com>, Fuad Tabba <tabba@...gle.com>, 
 Mark Rutland <mark.rutland@....com>, 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 v5 19/28] KVM: arm64: Provide assembly for SME register
 access

Provide versions of the SME state save and restore functions for the
hypervisor to allow it to restore ZA and ZT for guests.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 arch/arm64/include/asm/kvm_hyp.h |  3 +++
 arch/arm64/kvm/hyp/fpsimd.S      | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 0ad5a66e0d25..1c31d8b26aa9 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -115,6 +115,9 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
 void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
 void __sve_save_state(void *sve_pffr, u32 *fpsr, int save_ffr);
 void __sve_restore_state(void *sve_pffr, u32 *fpsr, int restore_ffr);
+int __sve_get_vl(void);
+void __sme_save_state(void const *state, bool restore_zt);
+void __sme_restore_state(void const *state, bool restore_zt);
 
 u64 __guest_enter(struct kvm_vcpu *vcpu);
 
diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
index 6e16cbfc5df2..44a1b0a483da 100644
--- a/arch/arm64/kvm/hyp/fpsimd.S
+++ b/arch/arm64/kvm/hyp/fpsimd.S
@@ -29,3 +29,29 @@ SYM_FUNC_START(__sve_save_state)
 	sve_save 0, x1, x2, 3
 	ret
 SYM_FUNC_END(__sve_save_state)
+
+SYM_FUNC_START(__sve_get_vl)
+	_sve_rdvl	0, 1
+	ret
+SYM_FUNC_END(__sve_get_vl)
+
+SYM_FUNC_START(__sme_save_state)
+	_sme_rdsvl	2, 1		// x2 = VL/8
+	sme_save_za 0, x2, 12		// Leaves x0 pointing to the end of ZA
+
+	cbz	x1, 1f
+	_str_zt 0
+1:
+	ret
+SYM_FUNC_END(__sme_save_state)
+
+SYM_FUNC_START(__sme_restore_state)
+	_sme_rdsvl	2, 1		// x2 = VL/8
+	sme_load_za	0, x2, 12	// Leaves x0 pointing to end of ZA
+
+	cbz	x1, 1f
+	_ldr_zt 0
+
+1:
+	ret
+SYM_FUNC_END(__sme_restore_state)

-- 
2.39.5