From 91f65debbe7af0f2f3e4db6fc5c6dc0869ea3fe7 Mon Sep 17 00:00:00 2001 From: Chen Qun Date: Thu, 6 Aug 2020 16:14:40 +0800 Subject: [PATCH] target/arm: Allow ID registers to synchronize to KVM There are 2 steps to synchronize the values of system registers from CPU state to KVM: 1. write to the values of system registers from CPU state to (index,value) list by write_cpustate_to_list; 2. write the values in (index,value) list to KVM by write_list_to_kvmstate; In step 1, the values of constant system registers are not allowed to write to (index,value) list. However, a constant system register is CONSTANT for guest but not for QEMU, which means, QEMU can set/modify the value of constant system registers that is different from phsical registers when startup. But if KVM is enabled, guest can not read the values of the system registers which QEMU set unless they can be written to (index,value) list. And why not try to write to KVM if kvm_sync is true? At the moment we call write_cpustate_to_list, all ID registers are contant, including ID_PFR1_EL1 and ID_AA64PFR0_EL1 because GIC has been initialized. Hence, let's give all ID registers a chance to write to KVM. If the write is successful, then write to (index,value) list. Signed-off-by: zhanghailiang Signed-off-by: Peng Liang Signed-off-by: Dongxu Sun --- ...w-ID-registers-to-synchronize-to-KVM.patch | 161 ++++++++++++++++++ 1 file changed, 161 insertions(+) create mode 100644 target-arm-Allow-ID-registers-to-synchronize-to-KVM.patch diff --git a/target-arm-Allow-ID-registers-to-synchronize-to-KVM.patch b/target-arm-Allow-ID-registers-to-synchronize-to-KVM.patch new file mode 100644 index 0000000..8464571 --- /dev/null +++ b/target-arm-Allow-ID-registers-to-synchronize-to-KVM.patch @@ -0,0 +1,161 @@ +From 0272c52e36ab95389e665ca19b129178b0b46eac Mon Sep 17 00:00:00 2001 +From: Peng Liang +Date: Thu, 6 Aug 2020 16:14:40 +0800 +Subject: [PATCH] target/arm: Allow ID registers to synchronize to KVM + +There are 2 steps to synchronize the values of system registers from +CPU state to KVM: +1. write to the values of system registers from CPU state to + (index,value) list by write_cpustate_to_list; +2. write the values in (index,value) list to KVM by + write_list_to_kvmstate; + +In step 1, the values of constant system registers are not allowed to +write to (index,value) list. However, a constant system register is +CONSTANT for guest but not for QEMU, which means, QEMU can set/modify +the value of constant system registers that is different from phsical +registers when startup. But if KVM is enabled, guest can not read the +values of the system registers which QEMU set unless they can be written +to (index,value) list. And why not try to write to KVM if kvm_sync is +true? + +At the moment we call write_cpustate_to_list, all ID registers are +contant, including ID_PFR1_EL1 and ID_AA64PFR0_EL1 because GIC has been +initialized. Hence, let's give all ID registers a chance to write to +KVM. If the write is successful, then write to (index,value) list. + +Signed-off-by: zhanghailiang +Signed-off-by: Peng Liang +Signed-off-by: Dongxu Sun +--- + target/arm/helper.c | 31 ++++++++++++++++++++----------- + target/arm/kvm.c | 38 ++++++++++++++++++++++++++++++++++++++ + target/arm/kvm_arm.h | 3 +++ + 3 files changed, 61 insertions(+), 11 deletions(-) + +diff --git a/target/arm/helper.c b/target/arm/helper.c +index b8ea1dc1f6..79f77705c3 100644 +--- a/target/arm/helper.c ++++ b/target/arm/helper.c +@@ -35,6 +35,7 @@ + #include "exec/cpu_ldst.h" + #include "semihosting/common-semi.h" + #endif ++#include "kvm_arm.h" + + #define ARM_CPU_FREQ 1000000000 /* FIXME: 1 GHz, should be configurable */ + #define PMCR_NUM_COUNTERS 4 /* QEMU IMPDEF choice */ +@@ -149,30 +150,38 @@ bool write_cpustate_to_list(ARMCPU *cpu, bool kvm_sync) + ok = false; + continue; + } +- if (ri->type & ARM_CP_NO_RAW) { ++ /* ++ * (Op0, Op1, CRn, CRm, Op2) of ID registers is (3, 0, 0, crm, op2), ++ * where 1<=crm<8, 0<=op2<8. Let's give ID registers a chance to ++ * synchronize to kvm. ++ */ ++ if ((ri->type & ARM_CP_NO_RAW) && !(kvm_sync && ++ ri->opc0 == 3 && ri->opc1 == 0 && ri->crn == 0 && ri->crm > 0)) { + continue; + } + + newval = read_raw_cp_reg(&cpu->env, ri); + if (kvm_sync) { +- /* +- * Only sync if the previous list->cpustate sync succeeded. +- * Rather than tracking the success/failure state for every +- * item in the list, we just recheck "does the raw write we must +- * have made in write_list_to_cpustate() read back OK" here. +- */ +- uint64_t oldval = cpu->cpreg_values[i]; ++ /* Only sync if we can sync to KVM successfully. */ ++ uint64_t oldval; ++ uint64_t kvmval; + ++ if (kvm_arm_get_one_reg(cpu, cpu->cpreg_indexes[i], &oldval)) { ++ continue; ++ } + if (oldval == newval) { + continue; + } + +- write_raw_cp_reg(&cpu->env, ri, oldval); +- if (read_raw_cp_reg(&cpu->env, ri) != oldval) { ++ if (kvm_arm_set_one_reg(cpu, cpu->cpreg_indexes[i], &newval)) { ++ continue; ++ } ++ if (kvm_arm_get_one_reg(cpu, cpu->cpreg_indexes[i], &kvmval) || ++ kvmval != newval) { + continue; + } + +- write_raw_cp_reg(&cpu->env, ri, newval); ++ kvm_arm_set_one_reg(cpu, cpu->cpreg_indexes[i], &oldval); + } + cpu->cpreg_values[i] = newval; + } +diff --git a/target/arm/kvm.c b/target/arm/kvm.c +index bbf1ce7ba3..59d556724f 100644 +--- a/target/arm/kvm.c ++++ b/target/arm/kvm.c +@@ -514,6 +514,44 @@ out: + return ret; + } + ++int kvm_arm_get_one_reg(ARMCPU *cpu, uint64_t regidx, uint64_t *target) ++{ ++ uint32_t v32; ++ int ret; ++ ++ switch (regidx & KVM_REG_SIZE_MASK) { ++ case KVM_REG_SIZE_U32: ++ ret = kvm_get_one_reg(CPU(cpu), regidx, &v32); ++ if (ret == 0) { ++ *target = v32; ++ } ++ return ret; ++ case KVM_REG_SIZE_U64: ++ return kvm_get_one_reg(CPU(cpu), regidx, target); ++ default: ++ return -1; ++ } ++} ++ ++int kvm_arm_set_one_reg(ARMCPU *cpu, uint64_t regidx, uint64_t *source) ++{ ++ uint32_t v32; ++ ++ switch (regidx & KVM_REG_SIZE_MASK) { ++ case KVM_REG_SIZE_U32: ++ v32 = *source; ++ if (v32 != *source) { ++ error_report("the value of source is too large"); ++ return -1; ++ } ++ return kvm_set_one_reg(CPU(cpu), regidx, &v32); ++ case KVM_REG_SIZE_U64: ++ return kvm_set_one_reg(CPU(cpu), regidx, source); ++ default: ++ return -1; ++ } ++} ++ + bool write_kvmstate_to_list(ARMCPU *cpu) + { + CPUState *cs = CPU(cpu); +diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h +index b7f78b5215..f8e0e64363 100644 +--- a/target/arm/kvm_arm.h ++++ b/target/arm/kvm_arm.h +@@ -528,4 +528,7 @@ static inline const char *its_class_name(void) + } + } + ++int kvm_arm_get_one_reg(ARMCPU *cpu, uint64_t regidx, uint64_t *target); ++int kvm_arm_set_one_reg(ARMCPU *cpu, uint64_t regidx, uint64_t *source); ++ + #endif +-- +2.27.0 +