KVM: arm64: Allow userspace to change ID_AA64ISAR{0-2}_EL1

Almost all of the features described by the ISA registers have no KVM
involvement. Allow userspace to change the value of these registers with
a couple exceptions:

 - MOPS is not writable as KVM does not currently virtualize FEAT_MOPS.

 - The PAuth fields are not writable as KVM requires both address and
   generic authentication be enabled.

Co-developed-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-7-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2023-10-03 23:04:02 +00:00
parent 9f9917bc71
commit 56d77aa8bd

View File

@ -1851,11 +1851,14 @@ static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu,
* from userspace.
*/
/* sys_reg_desc initialiser for known cpufeature ID registers */
#define ID_SANITISED(name) { \
#define ID_DESC(name) \
SYS_DESC(SYS_##name), \
.access = access_id_reg, \
.get_user = get_id_reg, \
.get_user = get_id_reg \
/* sys_reg_desc initialiser for known cpufeature ID registers */
#define ID_SANITISED(name) { \
ID_DESC(name), \
.set_user = set_id_reg, \
.visibility = id_visibility, \
.reset = kvm_read_sanitised_id_reg, \
@ -1864,15 +1867,22 @@ static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu,
/* sys_reg_desc initialiser for known cpufeature ID registers */
#define AA32_ID_SANITISED(name) { \
SYS_DESC(SYS_##name), \
.access = access_id_reg, \
.get_user = get_id_reg, \
ID_DESC(name), \
.set_user = set_id_reg, \
.visibility = aa32_id_visibility, \
.reset = kvm_read_sanitised_id_reg, \
.val = 0, \
}
/* sys_reg_desc initialiser for writable ID registers */
#define ID_WRITABLE(name, mask) { \
ID_DESC(name), \
.set_user = set_id_reg, \
.visibility = id_visibility, \
.reset = kvm_read_sanitised_id_reg, \
.val = mask, \
}
/*
* sys_reg_desc initialiser for architecturally unallocated cpufeature ID
* register with encoding Op0=3, Op1=0, CRn=0, CRm=crm, Op2=op2
@ -1894,9 +1904,7 @@ static unsigned int elx2_visibility(const struct kvm_vcpu *vcpu,
* RAZ for the guest.
*/
#define ID_HIDDEN(name) { \
SYS_DESC(SYS_##name), \
.access = access_id_reg, \
.get_user = get_id_reg, \
ID_DESC(name), \
.set_user = set_id_reg, \
.visibility = raz_visibility, \
.reset = kvm_read_sanitised_id_reg, \
@ -2075,9 +2083,15 @@ static const struct sys_reg_desc sys_reg_descs[] = {
ID_UNALLOCATED(5,7),
/* CRm=6 */
ID_SANITISED(ID_AA64ISAR0_EL1),
ID_SANITISED(ID_AA64ISAR1_EL1),
ID_SANITISED(ID_AA64ISAR2_EL1),
ID_WRITABLE(ID_AA64ISAR0_EL1, ~ID_AA64ISAR0_EL1_RES0),
ID_WRITABLE(ID_AA64ISAR1_EL1, ~(ID_AA64ISAR1_EL1_GPI |
ID_AA64ISAR1_EL1_GPA |
ID_AA64ISAR1_EL1_API |
ID_AA64ISAR1_EL1_APA)),
ID_WRITABLE(ID_AA64ISAR2_EL1, ~(ID_AA64ISAR2_EL1_RES0 |
ID_AA64ISAR2_EL1_MOPS |
ID_AA64ISAR2_EL1_APA3 |
ID_AA64ISAR2_EL1_GPA3)),
ID_UNALLOCATED(6,3),
ID_UNALLOCATED(6,4),
ID_UNALLOCATED(6,5),