diff options
| author | Mukesh Ojha <mukesh.ojha@oss.qualcomm.com> | 2025-10-10 23:17:07 +0530 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2025-10-13 14:26:36 +0100 |
| commit | c35dd838666d47de2848639234ec32e3ba22b49f (patch) | |
| tree | 7ecf9dd6e69394a2efa75b72cbc2dfd5bc358af9 | |
| parent | 9a7f87eb587da49993f47f44c4c5535d8de76750 (diff) | |
KVM: arm64: Guard PMSCR_EL1 initialization with SPE presence check
Commit efad60e46057 ("KVM: arm64: Initialize PMSCR_EL1 when in VHE")
does not perform sufficient check before initializing PMSCR_EL1 to 0
when running in VHE mode. On some platforms, this causes the system to
hang during boot, as EL3 has not delegated access to the Profiling
Buffer to the Non-secure world, nor does it reinject an UNDEF on sysreg
trap.
To avoid this issue, restrict the PMSCR_EL1 initialization to CPUs that
support Statistical Profiling Extension (FEAT_SPE) and have the
Profiling Buffer accessible in Non-secure EL1. This is determined via a
new helper `cpu_has_spe()` which checks both PMSVer and PMBIDR_EL1.P.
This ensures the initialization only affects CPUs where SPE is
implemented and usable, preventing boot failures on platforms where SPE
is not properly configured.
Fixes: efad60e46057 ("KVM: arm64: Initialize PMSCR_EL1 when in VHE")
Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/debug.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 3515a273eaa2..3ad6b7c6e4ba 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -15,6 +15,12 @@ #include <asm/kvm_arm.h> #include <asm/kvm_emulate.h> +static int cpu_has_spe(u64 dfr0) +{ + return cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_PMSVer_SHIFT) && + !(read_sysreg_s(SYS_PMBIDR_EL1) & PMBIDR_EL1_P); +} + /** * kvm_arm_setup_mdcr_el2 - configure vcpu mdcr_el2 value * @@ -77,13 +83,12 @@ void kvm_init_host_debug_data(void) *host_data_ptr(debug_brps) = SYS_FIELD_GET(ID_AA64DFR0_EL1, BRPs, dfr0); *host_data_ptr(debug_wrps) = SYS_FIELD_GET(ID_AA64DFR0_EL1, WRPs, dfr0); + if (cpu_has_spe(dfr0)) + host_data_set_flag(HAS_SPE); + if (has_vhe()) return; - if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_PMSVer_SHIFT) && - !(read_sysreg_s(SYS_PMBIDR_EL1) & PMBIDR_EL1_P)) - host_data_set_flag(HAS_SPE); - /* Check if we have BRBE implemented and available at the host */ if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_BRBE_SHIFT)) host_data_set_flag(HAS_BRBE); @@ -102,7 +107,7 @@ void kvm_init_host_debug_data(void) void kvm_debug_init_vhe(void) { /* Clear PMSCR_EL1.E{0,1}SPE which reset to UNKNOWN values. */ - if (SYS_FIELD_GET(ID_AA64DFR0_EL1, PMSVer, read_sysreg(id_aa64dfr0_el1))) + if (host_data_test_flag(HAS_SPE)) write_sysreg_el1(0, SYS_PMSCR); } |