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target/arm: Fill in ARMISARegisters for kvm64

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Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20181113180154.17903-3-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2018-11-19 15:29:07 +00:00 committed by Peter Maydell
parent 4674097c32
commit 9d60dea960
1 changed files with 88 additions and 2 deletions
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90
target/arm/kvm64.c
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@ -456,17 +456,40 @@ static inline void unset_feature(uint64_t *features, int feature)
*features &= ~(1ULL << feature);
}
static int read_sys_reg32(int fd, uint32_t *pret, uint64_t id)
{
uint64_t ret;
struct kvm_one_reg idreg = { .id = id, .addr = (uintptr_t)&ret };
int err;
assert((id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U64);
err = ioctl(fd, KVM_GET_ONE_REG, &idreg);
if (err < 0) {
return -1;
}
*pret = ret;
return 0;
}
static int read_sys_reg64(int fd, uint64_t *pret, uint64_t id)
{
struct kvm_one_reg idreg = { .id = id, .addr = (uintptr_t)pret };
assert((id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U64);
return ioctl(fd, KVM_GET_ONE_REG, &idreg);
}
bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
{
/* Identify the feature bits corresponding to the host CPU, and
* fill out the ARMHostCPUClass fields accordingly. To do this
* we have to create a scratch VM, create a single CPU inside it,
* and then query that CPU for the relevant ID registers.
* For AArch64 we currently don't care about ID registers at
* all; we just want to know the CPU type.
*/
int fdarray[3];
uint64_t features = 0;
int err;
/* Old kernels may not know about the PREFERRED_TARGET ioctl: however
* we know these will only support creating one kind of guest CPU,
* which is its preferred CPU type. Fortunately these old kernels
@ -487,8 +510,71 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
ahcf->target = init.target;
ahcf->dtb_compatible = "arm,arm-v8";
err = read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64pfr0,
ARM64_SYS_REG(3, 0, 0, 4, 0));
if (unlikely(err < 0)) {
/*
* Before v4.15, the kernel only exposed a limited number of system
* registers, not including any of the interesting AArch64 ID regs.
* For the most part we could leave these fields as zero with minimal
* effect, since this does not affect the values seen by the guest.
*
* However, it could cause problems down the line for QEMU,
* so provide a minimal v8.0 default.
*
* ??? Could read MIDR and use knowledge from cpu64.c.
* ??? Could map a page of memory into our temp guest and
* run the tiniest of hand-crafted kernels to extract
* the values seen by the guest.
* ??? Either of these sounds like too much effort just
* to work around running a modern host kernel.
*/
ahcf->isar.id_aa64pfr0 = 0x00000011; /* EL1&0, AArch64 only */
err = 0;
} 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_aa64isar0,
ARM64_SYS_REG(3, 0, 0, 6, 0));
err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64isar1,
ARM64_SYS_REG(3, 0, 0, 6, 1));
/*
* Note that if AArch32 support is not present in the host,
* the AArch32 sysregs are present to be read, but will
* return UNKNOWN values. This is neither better nor worse
* 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_isar0,
ARM64_SYS_REG(3, 0, 0, 2, 0));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar1,
ARM64_SYS_REG(3, 0, 0, 2, 1));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar2,
ARM64_SYS_REG(3, 0, 0, 2, 2));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar3,
ARM64_SYS_REG(3, 0, 0, 2, 3));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar4,
ARM64_SYS_REG(3, 0, 0, 2, 4));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar5,
ARM64_SYS_REG(3, 0, 0, 2, 5));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.id_isar6,
ARM64_SYS_REG(3, 0, 0, 2, 7));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.mvfr0,
ARM64_SYS_REG(3, 0, 0, 3, 0));
err |= read_sys_reg32(fdarray[2], &ahcf->isar.mvfr1,
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));
}
kvm_arm_destroy_scratch_host_vcpu(fdarray);
if (err < 0) {
return false;
}
/* We can assume any KVM supporting CPU is at least a v8
* with VFPv4+Neon; this in turn implies most of the other
* feature bits.