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@xxxxxxx>
Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Fuad Tabba <tabba@xxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Oliver Upton <oliver.upton@xxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 20 +++++-------------
arch/arm64/kvm/arm.c | 8 -------
arch/arm64/kvm/fpsimd.c | 2 --
arch/arm64/kvm/hyp/include/hyp/switch.h | 25 ++++++++++++++++++++--
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 2 +-
arch/arm64/kvm/hyp/nvhe/switch.c | 28 -------------------------
arch/arm64/kvm/hyp/vhe/switch.c | 8 -------
7 files changed, 29 insertions(+), 64 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7cfa024de4e34..f56c07568591f 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -624,23 +624,13 @@ struct kvm_host_data {
struct kvm_cpu_context host_ctxt;
/*
- * All pointers in this union are hyp VA.
+ * Hyp VA.
* sve_state is only used in pKVM and if system_supports_sve().
*/
- union {
- struct user_fpsimd_state *fpsimd_state;
- struct cpu_sve_state *sve_state;
- };
-
- union {
- /* HYP VA pointer to the host storage for FPMR */
- u64 *fpmr_ptr;
- /*
- * Used by pKVM only, as it needs to provide storage
- * for the host
- */
- u64 fpmr;
- };
+ struct cpu_sve_state *sve_state;
+
+ /* Used by pKVM only. */
+ u64 fpmr;
/* Ownership of the FP regs */
enum {
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 646e806c6ca69..027c8e9c4741f 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2461,14 +2461,6 @@ static void finalize_init_hyp_mode(void)
per_cpu_ptr_nvhe_sym(kvm_host_data, cpu)->sve_state =
kern_hyp_va(sve_state);
}
- } else {
- for_each_possible_cpu(cpu) {
- struct user_fpsimd_state *fpsimd_state;
-
- fpsimd_state = &per_cpu_ptr_nvhe_sym(kvm_host_data, cpu)->host_ctxt.fp_regs;
- per_cpu_ptr_nvhe_sym(kvm_host_data, cpu)->fpsimd_state =
- kern_hyp_va(fpsimd_state);
- }
}
}
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index ceeb0a4893aa7..332cb3904e68b 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -64,8 +64,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
*/
fpsimd_save_and_flush_cpu_state();
*host_data_ptr(fp_owner) = FP_STATE_FREE;
- *host_data_ptr(fpsimd_state) = NULL;
- *host_data_ptr(fpmr_ptr) = NULL;
host_data_clear_flag(HOST_SVE_ENABLED);
if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index f838a45665f26..c5b8a11ac4f50 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -375,7 +375,28 @@ static inline void __hyp_sve_save_host(void)
true);
}
-static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu);
+static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
+{
+ /*
+ * Non-protected kvm relies on the host restoring its sve state.
+ * Protected kvm restores the host's sve state as not to reveal that
+ * fpsimd was used by a guest nor leak upper sve bits.
+ */
+ if (system_supports_sve()) {
+ __hyp_sve_save_host();
+
+ /* Re-enable SVE traps if not supported for the guest vcpu. */
+ if (!vcpu_has_sve(vcpu))
+ cpacr_clear_set(CPACR_EL1_ZEN, 0);
+
+ } else {
+ __fpsimd_save_state(host_data_ptr(host_ctxt.fp_regs));
+ }
+
+ if (kvm_has_fpmr(kern_hyp_va(vcpu->kvm)))
+ *host_data_ptr(fpmr) = read_sysreg_s(SYS_FPMR);
+}
+
/*
* We trap the first access to the FP/SIMD to save the host context and
@@ -425,7 +446,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
isb();
/* Write out the host state if it's in the registers */
- if (host_owns_fp_regs())
+ if (is_protected_kvm_enabled() && host_owns_fp_regs())
kvm_hyp_save_fpsimd_host(vcpu);
/* Restore the guest state */
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 5c134520e1805..ad1abd5493862 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -83,7 +83,7 @@ static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
if (system_supports_sve())
__hyp_sve_restore_host();
else
- __fpsimd_restore_state(*host_data_ptr(fpsimd_state));
+ __fpsimd_restore_state(host_data_ptr(host_ctxt.fp_regs));
if (has_fpmr)
write_sysreg_s(*host_data_ptr(fpmr), SYS_FPMR);
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 6c846d033d24a..7a2d189176249 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -192,34 +192,6 @@ static bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code)
kvm_handle_pvm_sysreg(vcpu, exit_code));
}
-static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
-{
- /*
- * Non-protected kvm relies on the host restoring its sve state.
- * Protected kvm restores the host's sve state as not to reveal that
- * fpsimd was used by a guest nor leak upper sve bits.
- */
- if (unlikely(is_protected_kvm_enabled() && system_supports_sve())) {
- __hyp_sve_save_host();
-
- /* Re-enable SVE traps if not supported for the guest vcpu. */
- if (!vcpu_has_sve(vcpu))
- cpacr_clear_set(CPACR_EL1_ZEN, 0);
-
- } else {
- __fpsimd_save_state(*host_data_ptr(fpsimd_state));
- }
-
- if (kvm_has_fpmr(kern_hyp_va(vcpu->kvm))) {
- u64 val = read_sysreg_s(SYS_FPMR);
-
- if (unlikely(is_protected_kvm_enabled()))
- *host_data_ptr(fpmr) = val;
- else
- **host_data_ptr(fpmr_ptr) = val;
- }
-}
-
static const exit_handler_fn hyp_exit_handlers[] = {
[0 ... ESR_ELx_EC_MAX] = NULL,
[ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15_32,
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index b5b9dbaf1fdd6..e8a07d4bb546b 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -413,14 +413,6 @@ static bool kvm_hyp_handle_eret(struct kvm_vcpu *vcpu, u64 *exit_code)
return true;
}
-static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
-{
- __fpsimd_save_state(*host_data_ptr(fpsimd_state));
-
- if (kvm_has_fpmr(vcpu->kvm))
- **host_data_ptr(fpmr_ptr) = read_sysreg_s(SYS_FPMR);
-}
-
static bool kvm_hyp_handle_tlbi_el2(struct kvm_vcpu *vcpu, u64 *exit_code)
{
int ret = -EINVAL;
--
2.30.2
