Now that the driver tells us whether TRBE was used or not we can use that. Except in pKVM where the host isn't trusted we keep the existing feature + sysreg check.
Now in the normal nVHE case, TRBE save and restore are gated by flag checks on kvm_host_data.
Instead of using a magic value of host_debug_state.trfcr_el1 to determine whether to restore, add a flag. This will also simplify the logic in the next commit where restoration but no disabling is required.
Signed-off-by: James Clark james.clark@linaro.org --- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/kvm/hyp/nvhe/debug-sr.c | 51 +++++++++++++++++++++++------- 2 files changed, 41 insertions(+), 12 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index b1dccac996a6..a8846689512b 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -947,6 +947,8 @@ struct kvm_vcpu_arch { #define HOST_STATE_SPE_EN __kvm_single_flag(state, BIT(0)) /* TRBLIMITR_EL1_E is set (TRBE trace buffer enabled) */ #define HOST_STATE_TRBE_EN __kvm_single_flag(state, BIT(1)) +/* Hyp modified TRFCR */ +#define HOST_STATE_RESTORE_TRFCR __kvm_single_flag(state, BIT(2))
/* Pointer to the vcpu's SVE FFR for sve_{save,load}_state() */ #define vcpu_sve_pffr(vcpu) (kern_hyp_va((vcpu)->arch.sve_state) + \ diff --git a/arch/arm64/kvm/hyp/nvhe/debug-sr.c b/arch/arm64/kvm/hyp/nvhe/debug-sr.c index 578c549af3c6..17c23e52f5f4 100644 --- a/arch/arm64/kvm/hyp/nvhe/debug-sr.c +++ b/arch/arm64/kvm/hyp/nvhe/debug-sr.c @@ -63,32 +63,55 @@ static void __debug_restore_spe(void) *host_data_ptr(host_debug_state.pmscr_el1) = 0; }
-static void __debug_save_trace(u64 *trfcr_el1) +static bool __debug_should_save_trace(void) { - *trfcr_el1 = 0; + /* pKVM reads the state for itself rather than trusting the host */ + if (unlikely(is_protected_kvm_enabled())) { + /* Always disable any trace regardless of TRBE */ + if (read_sysreg_el1(SYS_TRFCR) & + (TRFCR_ELx_E0TRE | TRFCR_ELx_ExTRE)) + return true; + + /* + * Trace could already be disabled but TRBE buffer + * might still need to be drained if it was in use. + */ + if (host_data_get_flag(HOST_FEAT_HAS_TRBE)) + return read_sysreg_s(SYS_TRBLIMITR_EL1) & + TRBLIMITR_EL1_E; + } + + return host_data_get_flag(HOST_STATE_TRBE_EN); +}
- /* Check if the TRBE is enabled */ - if (!(read_sysreg_s(SYS_TRBLIMITR_EL1) & TRBLIMITR_EL1_E)) - return; +static void __debug_save_trace(void) +{ /* * Prohibit trace generation while we are in guest. * Since access to TRFCR_EL1 is trapped, the guest can't * modify the filtering set by the host. */ - *trfcr_el1 = read_sysreg_el1(SYS_TRFCR); + *host_data_ptr(host_debug_state.trfcr_el1) = read_sysreg_el1(SYS_TRFCR); write_sysreg_el1(0, SYS_TRFCR); isb(); /* Drain the trace buffer to memory */ tsb_csync(); + + host_data_set_flag(HOST_STATE_RESTORE_TRFCR); }
-static void __debug_restore_trace(u64 trfcr_el1) +static void __debug_restore_trace(void) { - if (!trfcr_el1) + u64 trfcr_el1; + + if (!host_data_get_flag(HOST_STATE_RESTORE_TRFCR)) return;
/* Restore trace filter controls */ + trfcr_el1 = *host_data_ptr(host_debug_state.trfcr_el1); + *host_data_ptr(host_debug_state.trfcr_el1) = read_sysreg_el1(SYS_TRFCR); write_sysreg_el1(trfcr_el1, SYS_TRFCR); + host_data_clear_flag(HOST_STATE_RESTORE_TRFCR); }
void __debug_save_host_buffers_nvhe(void) @@ -97,9 +120,14 @@ void __debug_save_host_buffers_nvhe(void) if (__debug_spe_enabled()) __debug_save_spe();
+ /* Any trace filtering requires TRFCR register */ + if (!host_data_get_flag(HOST_FEAT_HAS_TRF)) + return; + /* Disable and flush Self-Hosted Trace generation */ - if (host_data_get_flag(HOST_FEAT_HAS_TRBE)) - __debug_save_trace(host_data_ptr(host_debug_state.trfcr_el1)); + if (__debug_should_save_trace()) + __debug_save_trace(); + }
void __debug_switch_to_guest(struct kvm_vcpu *vcpu) @@ -110,8 +138,7 @@ void __debug_switch_to_guest(struct kvm_vcpu *vcpu) void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu) { __debug_restore_spe(); - if (host_data_get_flag(HOST_FEAT_HAS_TRBE)) - __debug_restore_trace(*host_data_ptr(host_debug_state.trfcr_el1)); + __debug_restore_trace(); }
void __debug_switch_to_host(struct kvm_vcpu *vcpu)