From b520ac7fc1727b0b7fa79d1e0cb9c8b2ba3e0282 Mon Sep 17 00:00:00 2001 From: "Huawei Technologies Co., Ltd" Date: Fri, 14 Feb 2020 17:51:07 +0000 Subject: [PATCH] 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 (cherry-picked from commit 1548a7b2ad621a31b4216ed703b6d658a2ecf0d0) Signed-off-by: Peng Liang --- ...-debug-related-ID-registers-from-KVM.patch | 133 ++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 target-arm-Read-debug-related-ID-registers-from-KVM.patch diff --git a/target-arm-Read-debug-related-ID-registers-from-KVM.patch b/target-arm-Read-debug-related-ID-registers-from-KVM.patch new file mode 100644 index 0000000..ec1706a --- /dev/null +++ b/target-arm-Read-debug-related-ID-registers-from-KVM.patch @@ -0,0 +1,133 @@ +From 58cd6440c5a50d5ef9cc85c0566486683a8bf0f4 Mon Sep 17 00:00:00 2001 +From: Peter Maydell +Date: Fri, 14 Feb 2020 17:51:07 +0000 +Subject: [PATCH] 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 +(cherry-picked from commit 1548a7b2ad621a31b4216ed703b6d658a2ecf0d0) +Signed-off-by: Peng Liang +--- + 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 a78c30c355..56d8cd8ce6 100644 +--- a/target/arm/cpu.h ++++ b/target/arm/cpu.h +@@ -848,6 +848,11 @@ 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 2247148e25..e984d52dd2 100644 +--- a/target/arm/kvm32.c ++++ b/target/arm/kvm32.c +@@ -93,6 +93,9 @@ 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); +@@ -121,6 +124,11 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) + ahcf->isar.id_mmfr4 = 0; + } + ++ /* ++ * 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 276d146600..2a88b8df37 100644 +--- a/target/arm/kvm64.c ++++ b/target/arm/kvm64.c +@@ -533,6 +533,10 @@ 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, +@@ -551,6 +555,8 @@ 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_mmfr0, + ARM64_SYS_REG(3, 0, 0, 1, 4)); + err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_mmfr1, +@@ -582,6 +588,36 @@ 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; ++ } + } + + kvm_arm_destroy_scratch_host_vcpu(fdarray); +-- +2.23.0 +