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KVM: arm64: Do not map the host fpsimd state to hyp in pKVM

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pKVM maintains its own state at EL2 for tracking the host fpsimd
state. Therefore, no need to map and share the host's view with
it.

Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-12-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Fuad Tabba 2024-04-23 16:05:19 +01:00 committed by Marc Zyngier
parent cfbdc546b6
commit d48965bc47
3 changed files with 4 additions and 31 deletions
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3
arch/arm64/include/asm/kvm_host.h
View File

@ -663,8 +663,6 @@ struct kvm_vcpu_arch {
struct kvm_guest_debug_arch vcpu_debug_state;
struct kvm_guest_debug_arch external_debug_state;
struct task_struct *parent_task;
/* VGIC state */
struct vgic_cpu vgic_cpu;
struct arch_timer_cpu timer_cpu;
@ -1262,7 +1260,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);
void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu);
static inline bool kvm_pmu_counter_deferred(struct perf_event_attr *attr)
{

31
arch/arm64/kvm/fpsimd.c
View File

@ -14,19 +14,6 @@
#include <asm/kvm_mmu.h>
#include <asm/sysreg.h>
void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
{
struct task_struct *p = vcpu->arch.parent_task;
struct user_fpsimd_state *fpsimd;
if (!is_protected_kvm_enabled() || !p)
return;
fpsimd = &p->thread.uw.fpsimd_state;
kvm_unshare_hyp(fpsimd, fpsimd + 1);
put_task_struct(p);
}
/*
* Called on entry to KVM_RUN unless this vcpu previously ran at least
* once and the most recent prior KVM_RUN for this vcpu was called from
@ -38,28 +25,18 @@ void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
*/
int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
{
struct user_fpsimd_state *fpsimd = &current->thread.uw.fpsimd_state;
int ret;
struct user_fpsimd_state *fpsimd = &current->thread.uw.fpsimd_state;
kvm_vcpu_unshare_task_fp(vcpu);
/* pKVM has its own tracking of the host fpsimd state. */
if (is_protected_kvm_enabled())
return 0;
/* Make sure the host task fpsimd state is visible to hyp: */
ret = kvm_share_hyp(fpsimd, fpsimd + 1);
if (ret)
return ret;
/*
* We need to keep current's task_struct pinned until its data has been
* unshared with the hypervisor to make sure it is not re-used by the
* kernel and donated to someone else while already shared -- see
* kvm_vcpu_unshare_task_fp() for the matching put_task_struct().
*/
if (is_protected_kvm_enabled()) {
get_task_struct(current);
vcpu->arch.parent_task = current;
}
return 0;
}

1
arch/arm64/kvm/reset.c
View File

@ -151,7 +151,6 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
void *sve_state = vcpu->arch.sve_state;
kvm_vcpu_unshare_task_fp(vcpu);
kvm_unshare_hyp(vcpu, vcpu + 1);
if (sve_state)
kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));