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KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2

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With HCR_EL2.NV bit set, accesses to EL12 registers in the virtual EL2
trap to EL2. Handle those traps just like we do for EL1 registers.

One exception is CNTKCTL_EL12. We don't trap on CNTKCTL_EL1 for non-VHE
virtual EL2 because we don't have to. However, accessing CNTKCTL_EL12
will trap since it's one of the EL12 registers controlled by HCR_EL2.NV
bit.  Therefore, add a handler for it and don't treat it as a
non-trap-registers when preparing a shadow context.

These registers, being only a view on their EL1 counterpart, are
permanently hidden from userspace.

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
[maz: EL12_REG(), register visibility]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230209175820.1939006-17-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Jintack Lim 2023-02-09 17:58:18 +00:00 committed by Oliver Upton
parent e6b367db0f
commit 280b748e87
1 changed files with 37 additions and 0 deletions
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37
arch/arm64/kvm/sys_regs.c
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@ -1482,6 +1482,26 @@ static unsigned int el2_visibility(const struct kvm_vcpu *vcpu,
.val = v, \
}
/*
* EL{0,1}2 registers are the EL2 view on an EL0 or EL1 register when
* HCR_EL2.E2H==1, and only in the sysreg table for convenience of
* handling traps. Given that, they are always hidden from userspace.
*/
static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd)
{
return REG_HIDDEN_USER;
}
#define EL12_REG(name, acc, rst, v) { \
SYS_DESC(SYS_##name##_EL12), \
.access = acc, \
.reset = rst, \
.reg = name##_EL1, \
.val = v, \
.visibility = elx2_visibility, \
}
/* sys_reg_desc initialiser for known cpufeature ID registers */
#define ID_SANITISED(name) { \
SYS_DESC(SYS_##name), \
@ -2031,6 +2051,23 @@ static const struct sys_reg_desc sys_reg_descs[] = {
EL2_REG(CNTVOFF_EL2, access_rw, reset_val, 0),
EL2_REG(CNTHCTL_EL2, access_rw, reset_val, 0),
EL12_REG(SCTLR, access_vm_reg, reset_val, 0x00C50078),
EL12_REG(CPACR, access_rw, reset_val, 0),
EL12_REG(TTBR0, access_vm_reg, reset_unknown, 0),
EL12_REG(TTBR1, access_vm_reg, reset_unknown, 0),
EL12_REG(TCR, access_vm_reg, reset_val, 0),
{ SYS_DESC(SYS_SPSR_EL12), access_spsr},
{ SYS_DESC(SYS_ELR_EL12), access_elr},
EL12_REG(AFSR0, access_vm_reg, reset_unknown, 0),
EL12_REG(AFSR1, access_vm_reg, reset_unknown, 0),
EL12_REG(ESR, access_vm_reg, reset_unknown, 0),
EL12_REG(FAR, access_vm_reg, reset_unknown, 0),
EL12_REG(MAIR, access_vm_reg, reset_unknown, 0),
EL12_REG(AMAIR, access_vm_reg, reset_amair_el1, 0),
EL12_REG(VBAR, access_rw, reset_val, 0),
EL12_REG(CONTEXTIDR, access_vm_reg, reset_val, 0),
EL12_REG(CNTKCTL, access_rw, reset_val, 0),
EL2_REG(SP_EL2, NULL, reset_unknown, 0),
};