packages/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

target/arm: Read debug-related ID registers from KVM

Browse Source 
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 <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200214175116.9164-13-peter.maydell@linaro.org
(cherry-picked from commit 1548a7b2ad621a31b4216ed703b6d658a2ecf0d0)
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
This commit is contained in:
Huawei Technologies Co., Ltd 2020-02-14 17:51:07 +00:00 committed by Euler Robot
parent d03485e959
commit b520ac7fc1
1 changed files with 133 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

133
target-arm-Read-debug-related-ID-registers-from-KVM.patch Normal file
View File

@ -0,0 +1,133 @@
From 58cd6440c5a50d5ef9cc85c0566486683a8bf0f4 Mon Sep 17 00:00:00 2001
From: Peter Maydell <peter.maydell@linaro.org>
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 <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200214175116.9164-13-peter.maydell@linaro.org
(cherry-picked from commit 1548a7b2ad621a31b4216ed703b6d658a2ecf0d0)
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
---
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