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KVM: arm64: Remove host FPSIMD saving for non-protected KVM

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[ Upstream commit 8eca7f6d51 ]

Now that the host eagerly saves its own FPSIMD/SVE/SME state,
non-protected KVM never needs to save the host FPSIMD/SVE/SME state,
and the code to do this is never used. Protected KVM still needs to
save/restore the host FPSIMD/SVE state to avoid leaking guest state to
the host (and to avoid revealing to the host whether the guest used
FPSIMD/SVE/SME), and that code needs to be retained.

Remove the unused code and data structures.

To avoid the need for a stub copy of kvm_hyp_save_fpsimd_host() in the
VHE hyp code, the nVHE/hVHE version is moved into the shared switch
header, where it is only invoked when KVM is in protected mode.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250210195226.1215254-3-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mark Rutland
2025-04-08 19:10:03 +01:00
committed by Greg Kroah-Hartman
parent 5289ac43b6
commit 08ce0d1ee6
3 changed files with 1 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/arm64/include/asm/kvm_host.h
-1
View File
@@ -333,7 +333,6 @@ struct kvm_vcpu_arch {
struct kvm_guest_debug_arch external_debug_state;
struct thread_info *host_thread_info; /* hyp VA */
struct user_fpsimd_state *host_fpsimd_state; /* hyp VA */
struct {
/* {Break,watch}point registers */
arch/arm64/kvm/fpsimd.c
-1
View File
@@ -55,7 +55,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
}
vcpu->arch.host_thread_info = kern_hyp_va(ti);
vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
error:
return ret;
}
arch/arm64/kvm/hyp/include/hyp/switch.h
+1 -5
View File
@@ -251,11 +251,7 @@ static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu)
}
isb();
if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
}
/* Restore the guest state */
if (sve_guest)
__hyp_sve_restore_guest(vcpu);
else