From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>,
Zhang Lei <zhang.lei@jp.fujitsu.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Andre Przywara <andre.przywara@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
Mark Brown <broonie@kernel.org>
Subject: [PATCH v3 4/7] arm64/fpsimd: Stop using TIF_SVE to manage register saving in KVM
Date: Mon, 15 Aug 2022 23:55:26 +0100 [thread overview]
Message-ID: <20220815225529.930315-5-broonie@kernel.org> (raw)
In-Reply-To: <20220815225529.930315-1-broonie@kernel.org>
Now that we are explicitly telling the host FP code which register state
it needs to save we can remove the manipulation of TIF_SVE from the KVM
code, simplifying it and allowing us to optimise our handling of normal
tasks. Remove the manipulation of TIF_SVE from KVM and instead rely on
to_save to ensure we save the correct data for it.
Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/kernel/fpsimd.c | 22 ++++------------------
arch/arm64/kvm/fpsimd.c | 3 ---
2 files changed, 4 insertions(+), 21 deletions(-)
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 7be20ced2c45..aaea2dc02cbd 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -436,8 +436,8 @@ static void task_fpsimd_load(void)
* last, if KVM is involved this may be the guest VM context rather
* than the host thread for the VM pointed to by current. This means
* that we must always reference the state storage via last rather
- * than via current, other than the TIF_ flags which KVM will
- * carefully maintain for us.
+ * than via current, if we are saving KVM state then it will have
+ * ensured that the type of registers to save is set in last->to_save.
*/
static void fpsimd_save(void)
{
@@ -454,27 +454,13 @@ static void fpsimd_save(void)
if (test_thread_flag(TIF_FOREIGN_FPSTATE))
return;
- if (test_thread_flag(TIF_SVE)) {
+ if ((last->to_save == FP_STATE_TASK && test_thread_flag(TIF_SVE)) ||
+ last->to_save == FP_STATE_SVE) {
save_sve_regs = true;
save_ffr = true;
vl = last->sve_vl;
}
- /*
- * For now we're just validating that the requested state is
- * consistent with what we'd otherwise work out.
- */
- switch (last->to_save) {
- case FP_STATE_TASK:
- break;
- case FP_STATE_FPSIMD:
- WARN_ON_ONCE(save_sve_regs);
- break;
- case FP_STATE_SVE:
- WARN_ON_ONCE(!save_sve_regs);
- break;
- }
-
if (system_supports_sme()) {
u64 *svcr = last->svcr;
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index db0b2bacaeb8..8a79823fce68 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -151,7 +151,6 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
&vcpu->arch.fp_type, fp_type);
clear_thread_flag(TIF_FOREIGN_FPSTATE);
- update_thread_flag(TIF_SVE, vcpu_has_sve(vcpu));
}
}
@@ -208,7 +207,5 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0);
}
- update_thread_flag(TIF_SVE, 0);
-
local_irq_restore(flags);
}
--
2.30.2
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next prev parent reply other threads:[~2022-08-15 23:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-15 22:55 [PATCH v3 0/7] arm64/sve: Clean up KVM integration and optimise syscalls Mark Brown
2022-08-15 22:55 ` [PATCH v3 1/7] KVM: arm64: Discard any SVE state when entering KVM guests Mark Brown
2022-09-20 16:44 ` Marc Zyngier
2022-09-20 20:21 ` Mark Brown
2022-09-21 17:31 ` Marc Zyngier
2022-09-22 11:44 ` Mark Brown
2022-08-15 22:55 ` [PATCH v3 2/7] arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE Mark Brown
2022-09-20 17:14 ` Marc Zyngier
2022-09-20 18:09 ` Mark Brown
2022-09-20 18:30 ` Marc Zyngier
2022-08-15 22:55 ` [PATCH v3 3/7] arm64/fpsimd: Have KVM explicitly say which FP registers to save Mark Brown
2022-09-20 17:52 ` Marc Zyngier
2022-09-20 18:32 ` Mark Brown
2022-09-21 17:47 ` Marc Zyngier
2022-09-22 12:18 ` Mark Brown
2022-08-15 22:55 ` Mark Brown [this message]
2022-09-20 18:04 ` [PATCH v3 4/7] arm64/fpsimd: Stop using TIF_SVE to manage register saving in KVM Marc Zyngier
2022-09-20 18:53 ` Mark Brown
2022-08-15 22:55 ` [PATCH v3 5/7] arm64/fpsimd: Load FP state based on recorded data type Mark Brown
2022-09-20 18:19 ` Marc Zyngier
2022-09-20 19:02 ` Mark Brown
2022-08-15 22:55 ` [PATCH v3 6/7] arm64/fpsimd: SME no longer requires SVE register state Mark Brown
2022-08-15 22:55 ` [PATCH v3 7/7] arm64/sve: Leave SVE enabled on syscall if we don't context switch Mark Brown
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