From: Oliver Upton <oliver.upton@linux.dev> mainline inclusion from mainline-v6.7-rc1 commit 56d77aa8bdf527f3b767fa27a3f135769151c92d category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IBN3WI CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------------------------------------ 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> --- arch/arm64/kvm/sys_regs.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 674295207031..50db4032c92c 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1973,11 +1973,14 @@ 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, \ @@ -1986,15 +1989,22 @@ 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 @@ -2016,9 +2026,7 @@ 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, \ @@ -2255,9 +2263,15 @@ 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), -- 2.33.0