shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-08 03:40:35 +09:00
Code Issues Packages Projects Releases Wiki Activity

ANDROID: KVM: arm64: pkvm: Lazy host FP save/restore

Browse Source 
Implement lazy save/restore of the FPSIMD and SVE registers for the host
so that the guest register state remains live for a vCPU with
KVM_ARM64_FP_ENABLED set and the state is only switched in response to a
trap from the host.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Bug: 209580772
Change-Id: I6977740727964e297d1e658e8eaec4f0125cce48
Signed-off-by: Will Deacon <willdeacon@google.com>
This commit is contained in:
Marc Zyngier
2021-10-25 19:55:20 +01:00
committed by Will Deacon
parent 7d81b2a5e6
commit dc2fae6338
1 changed files with 62 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
arch/arm64/kvm/hyp/nvhe/hyp-main.c
View File

@@ -337,12 +337,43 @@ static void sync_shadow_state(struct kvm_vcpu *shadow_vcpu, u32 exit_reason)
struct pkvm_loaded_state {
/* loaded vcpu is HYP VA */
struct kvm_vcpu *vcpu;
bool is_shadow;
struct kvm_vcpu *vcpu;
bool is_shadow;
/*
* Host FPSIMD state. Written to when the guest accesses its
* own FPSIMD state, and read when the guest state is live and
* that it needs to be switched back to the host.
*
* Only valid when the KVM_ARM64_FP_ENABLED flag is set in the
* shadow structure.
*/
struct user_fpsimd_state host_fpsimd_state;
};
static DEFINE_PER_CPU(struct pkvm_loaded_state, loaded_state);
static void fpsimd_host_restore(void)
{
sysreg_clear_set(cptr_el2, CPTR_EL2_TZ | CPTR_EL2_TFP, 0);
isb();
if (unlikely(is_protected_kvm_enabled())) {
struct pkvm_loaded_state *state = this_cpu_ptr(&loaded_state);
if (state->is_shadow) {
__fpsimd_save_state(&state->vcpu->arch.ctxt.fp_regs);
__fpsimd_restore_state(&state->host_fpsimd_state);
state->vcpu->arch.flags &= ~KVM_ARM64_FP_ENABLED;
state->vcpu->arch.flags |= KVM_ARM64_FP_HOST;
}
}
if (system_supports_sve())
sve_cond_update_zcr_vq(ZCR_ELx_LEN_MASK, SYS_ZCR_EL2);
}
static void handle___pkvm_vcpu_load(struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -364,8 +395,8 @@ static void handle___pkvm_vcpu_load(struct kvm_cpu_context *host_ctxt)
state->is_shadow = state->vcpu != vcpu;
if (state->is_shadow) {
/* FIXME: we can't trust the validity of these pointers */
state->vcpu->arch.host_fpsimd_state = vcpu->arch.host_fpsimd_state;
state->vcpu->arch.host_fpsimd_state = &state->host_fpsimd_state;
state->vcpu->arch.flags |= KVM_ARM64_FP_HOST;
/* Propagate WFx trapping flags, trap ptrauth */
state->vcpu->arch.hcr_el2 &= ~(HCR_TWE | HCR_TWI |
@@ -376,10 +407,20 @@ static void handle___pkvm_vcpu_load(struct kvm_cpu_context *host_ctxt)
static void handle___pkvm_vcpu_put(struct kvm_cpu_context *host_ctxt)
{
struct pkvm_loaded_state *state = this_cpu_ptr(&loaded_state);
DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
/* "It's over and done with..." */
state->vcpu = NULL;
if (unlikely(is_protected_kvm_enabled())) {
struct pkvm_loaded_state *state = this_cpu_ptr(&loaded_state);
if (state->vcpu && state->is_shadow &&
state->vcpu->arch.pkvm.host_vcpu == kern_hyp_va(vcpu)) {
if (state->vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
fpsimd_host_restore();
/* "It's over and done with..." */
state->vcpu = NULL;
}
}
}
static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt)
@@ -397,6 +438,18 @@ static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt)
if (state->is_shadow)
sync_shadow_state(state->vcpu, ret);
if (state->vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
/*
* The guest has used the FP, trap all accesses
* from the host (both FP and SVE).
*/
u64 reg = CPTR_EL2_TFP;
if (system_supports_sve())
reg |= CPTR_EL2_TZ;
sysreg_clear_set(cptr_el2, 0, reg);
}
} else {
ret = __kvm_vcpu_run(kern_hyp_va(vcpu));
}
@@ -722,10 +775,9 @@ void handle_trap(struct kvm_cpu_context *host_ctxt)
case ESR_ELx_EC_SMC64:
handle_host_smc(host_ctxt);
break;
case ESR_ELx_EC_FP_ASIMD:
case ESR_ELx_EC_SVE:
sysreg_clear_set(cptr_el2, CPTR_EL2_TZ, 0);
isb();
sve_cond_update_zcr_vq(ZCR_ELx_LEN_MASK, SYS_ZCR_EL2);
fpsimd_host_restore();
break;
case ESR_ELx_EC_IABT_LOW:
case ESR_ELx_EC_DABT_LOW: