Proxmox-Port/linux-loongson
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson synced 2025-08-31 22:23:05 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

KVM: arm64: Treat CTR_EL0 as a VM feature ID register

Browse Source 
CTR_EL0 is currently handled as an invariant register, thus
guests will be presented with the host value of that register.

Add emulation for CTR_EL0 based on a per VM value. Userspace can
switch off DIC and IDC bits and reduce DminLine and IminLine sizes.
Naturally, ensure CTR_EL0 is trapped (HCR_EL2.TID2=1) any time that a
VM's CTR_EL0 differs from hardware.

Signed-off-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Link: https://lore.kernel.org/r/20240619174036.483943-8-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Sebastian Ott 2024-06-19 17:40:33 +00:00 committed by Oliver Upton
parent f1ff3fc520
commit 2843cae266
2 changed files with 14 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/arm64/include/asm/kvm_host.h
View File

@ -329,6 +329,8 @@ struct kvm_arch {
#define KVM_ARM_ID_REG_NUM (IDREG_IDX(sys_reg(3, 0, 0, 7, 7)) + 1)
u64 id_regs[KVM_ARM_ID_REG_NUM];
u64 ctr_el0;
/* Masks for VNCR-baked sysregs */
struct kvm_sysreg_masks *sysreg_masks;
@ -1335,6 +1337,8 @@ static inline u64 *__vm_id_reg(struct kvm_arch *ka, u32 reg)
switch (reg) {
case sys_reg(3, 0, 0, 1, 0) ... sys_reg(3, 0, 0, 7, 7):
return &ka->id_regs[IDREG_IDX(reg)];
case SYS_CTR_EL0:
return &ka->ctr_el0;
default:
WARN_ON_ONCE(1);
return NULL;

20
arch/arm64/kvm/sys_regs.c
View File

@ -1583,6 +1583,9 @@ static bool is_feature_id_reg(u32 encoding)
*/
static inline bool is_vm_ftr_id_reg(u32 id)
{
if (id == SYS_CTR_EL0)
return true;
return (sys_reg_Op0(id) == 3 && sys_reg_Op1(id) == 0 &&
sys_reg_CRn(id) == 0 && sys_reg_CRm(id) >= 1 &&
sys_reg_CRm(id) < 8);
@ -1898,7 +1901,7 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
if (p->is_write)
return write_to_read_only(vcpu, p, r);
p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0);
p->regval = kvm_read_vm_id_reg(vcpu->kvm, SYS_CTR_EL0);
return true;
}
@ -2487,7 +2490,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_CCSIDR2_EL1), undef_access },
{ SYS_DESC(SYS_SMIDR_EL1), undef_access },
{ SYS_DESC(SYS_CSSELR_EL1), access_csselr, reset_unknown, CSSELR_EL1 },
{ SYS_DESC(SYS_CTR_EL0), access_ctr },
ID_WRITABLE(CTR_EL0, CTR_EL0_DIC_MASK |
CTR_EL0_IDC_MASK |
CTR_EL0_DminLine_MASK |
CTR_EL0_IminLine_MASK),
{ SYS_DESC(SYS_SVCR), undef_access },
{ PMU_SYS_REG(PMCR_EL0), .access = access_pmcr, .reset = reset_pmcr,
@ -3725,18 +3731,11 @@ FUNCTION_INVARIANT(midr_el1)
FUNCTION_INVARIANT(revidr_el1)
FUNCTION_INVARIANT(aidr_el1)
static u64 get_ctr_el0(struct kvm_vcpu *v, const struct sys_reg_desc *r)
{
((struct sys_reg_desc *)r)->val = read_sanitised_ftr_reg(SYS_CTR_EL0);
return ((struct sys_reg_desc *)r)->val;
}
/* ->val is filled in by kvm_sys_reg_table_init() */
static struct sys_reg_desc invariant_sys_regs[] __ro_after_init = {
{ SYS_DESC(SYS_MIDR_EL1), NULL, get_midr_el1 },
{ SYS_DESC(SYS_REVIDR_EL1), NULL, get_revidr_el1 },
{ SYS_DESC(SYS_AIDR_EL1), NULL, get_aidr_el1 },
{ SYS_DESC(SYS_CTR_EL0), NULL, get_ctr_el0 },
};
static int get_invariant_sys_reg(u64 id, u64 __user *uaddr)
@ -4086,7 +4085,8 @@ static void vcpu_set_hcr(struct kvm_vcpu *vcpu)
vcpu->arch.hcr_el2 |= HCR_FWB;
if (cpus_have_final_cap(ARM64_HAS_EVT) &&
!cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE))
!cpus_have_final_cap(ARM64_MISMATCHED_CACHE_TYPE) &&
kvm_read_vm_id_reg(kvm, SYS_CTR_EL0) == read_sanitised_ftr_reg(SYS_CTR_EL0))
vcpu->arch.hcr_el2 |= HCR_TID4;
else
vcpu->arch.hcr_el2 |= HCR_TID2;