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target/arm: Allow ID registers to synchronize to KVM

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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 <zhang.zhanghailiang@huawei.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
(cherry-picked from commit f4e592d1235bbb1290b8bc3684cb57c4304d63dc)
This commit is contained in:
Huawei Technologies Co., Ltd 2020-08-06 16:14:40 +08:00 committed by Euler Robot
parent e3be4ea4ad
commit bd1a51d1dd
1 changed files with 161 additions and 0 deletions
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161
target-arm-Allow-ID-registers-to-synchronize-to-KVM.patch Normal file
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@ -0,0 +1,161 @@
From ad9e15e9ea89f29cece5c9f96517ec3c055178d0 Mon Sep 17 00:00:00 2001
From: Peng Liang <liangpeng10@huawei.com>
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 <zhang.zhanghailiang@huawei.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
(cherry-picked from commit f4e592d1235bbb1290b8bc3684cb57c4304d63dc)
---
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 459af43101..97b6b86197 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -32,6 +32,7 @@
#include "arm_ldst.h"
#include "exec/cpu_ldst.h"
#endif
+#include "kvm_arm.h"
#define ARM_CPU_FREQ 1000000000 /* FIXME: 1 GHz, should be configurable */
@@ -267,30 +268,38 @@ 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 4f131f687d..229b17cea0 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -457,6 +457,44 @@ 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 0de5f83ee8..9b7104d622 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -400,4 +400,7 @@ 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
--
2.23.0