From 1548a7b2ad621a31b4216ed703b6d658a2ecf0d0 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 14 Feb 2020 17:51:07 +0000 Subject: target/arm: Read debug-related ID registers from KVM Now we have isar_feature test functions that look at fields in the ID_AA64DFR0_EL1 and ID_DFR0 ID registers, add the code that reads these register values from KVM so that the checks behave correctly when we're using KVM. No isar_feature function tests ID_AA64DFR1_EL1 or DBGDIDR yet, but we add it to maintain the invariant that every field in the ARMISARegisters struct is populated for a KVM CPU and can be relied on. This requirement isn't actually written down yet, so add a note to the relevant comment. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20200214175116.9164-13-peter.maydell@linaro.org --- target/arm/cpu.h | 5 +++++ target/arm/kvm32.c | 8 ++++++++ target/arm/kvm64.c | 36 ++++++++++++++++++++++++++++++++++++ 3 files changed, 49 insertions(+) diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 3c996db3e4..e043932fcb 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -853,6 +853,11 @@ struct ARMCPU { * prefix means a constant register. * Some of these registers are split out into a substructure that * is shared with the translators to control the ISA. + * + * Note that if you add an ID register to the ARMISARegisters struct + * you need to also update the 32-bit and 64-bit versions of the + * kvm_arm_get_host_cpu_features() function to correctly populate the + * field by reading the value from the KVM vCPU. */ struct ARMISARegisters { uint32_t id_isar0; diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c index 3a8b437eef..bca02553b2 100644 --- a/target/arm/kvm32.c +++ b/target/arm/kvm32.c @@ -97,6 +97,9 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) ahcf->isar.id_isar6 = 0; } + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_dfr0, + ARM_CP15_REG32(0, 0, 1, 2)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.mvfr0, KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP | KVM_REG_ARM_VFP_MVFR0); @@ -108,6 +111,11 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) * Fortunately there is not yet anything in there that affects migration. */ + /* + * There is no way to read DBGDIDR, because currently 32-bit KVM + * doesn't implement debug at all. Leave it at zero. + */ + kvm_arm_destroy_scratch_host_vcpu(fdarray); if (err < 0) { diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c index 3bae9e4a66..e8d7cea74c 100644 --- a/target/arm/kvm64.c +++ b/target/arm/kvm64.c @@ -541,6 +541,10 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) } else { err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64pfr1, ARM64_SYS_REG(3, 0, 0, 4, 1)); + err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64dfr0, + ARM64_SYS_REG(3, 0, 0, 5, 0)); + err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64dfr1, + ARM64_SYS_REG(3, 0, 0, 5, 1)); err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64isar0, ARM64_SYS_REG(3, 0, 0, 6, 0)); err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64isar1, @@ -559,6 +563,8 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) * than skipping the reads and leaving 0, as we must avoid * considering the values in every case. */ + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_dfr0, + ARM64_SYS_REG(3, 0, 0, 1, 2)); err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar0, ARM64_SYS_REG(3, 0, 0, 2, 0)); err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar1, @@ -580,6 +586,36 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) ARM64_SYS_REG(3, 0, 0, 3, 1)); err |= read_sys_reg32(fdarray[2], &ahcf->isar.mvfr2, ARM64_SYS_REG(3, 0, 0, 3, 2)); + + /* + * DBGDIDR is a bit complicated because the kernel doesn't + * provide an accessor for it in 64-bit mode, which is what this + * scratch VM is in, and there's no architected "64-bit sysreg + * which reads the same as the 32-bit register" the way there is + * for other ID registers. Instead we synthesize a value from the + * AArch64 ID_AA64DFR0, the same way the kernel code in + * arch/arm64/kvm/sys_regs.c:trap_dbgidr() does. + * We only do this if the CPU supports AArch32 at EL1. + */ + if (FIELD_EX32(ahcf->isar.id_aa64pfr0, ID_AA64PFR0, EL1) >= 2) { + int wrps = FIELD_EX64(ahcf->isar.id_aa64dfr0, ID_AA64DFR0, WRPS); + int brps = FIELD_EX64(ahcf->isar.id_aa64dfr0, ID_AA64DFR0, BRPS); + int ctx_cmps = + FIELD_EX64(ahcf->isar.id_aa64dfr0, ID_AA64DFR0, CTX_CMPS); + int version = 6; /* ARMv8 debug architecture */ + bool has_el3 = + !!FIELD_EX32(ahcf->isar.id_aa64pfr0, ID_AA64PFR0, EL3); + uint32_t dbgdidr = 0; + + dbgdidr = FIELD_DP32(dbgdidr, DBGDIDR, WRPS, wrps); + dbgdidr = FIELD_DP32(dbgdidr, DBGDIDR, BRPS, brps); + dbgdidr = FIELD_DP32(dbgdidr, DBGDIDR, CTX_CMPS, ctx_cmps); + dbgdidr = FIELD_DP32(dbgdidr, DBGDIDR, VERSION, version); + dbgdidr = FIELD_DP32(dbgdidr, DBGDIDR, NSUHD_IMP, has_el3); + dbgdidr = FIELD_DP32(dbgdidr, DBGDIDR, SE_IMP, has_el3); + dbgdidr |= (1 << 15); /* RES1 bit */ + ahcf->isar.dbgdidr = dbgdidr; + } } sve_supported = ioctl(fdarray[0], KVM_CHECK_EXTENSION, KVM_CAP_ARM_SVE) > 0; -- cgit v1.2.3