CNTHVS_TVAL_EL2, Counter-timer Secure Virtual Timer TimerValue register (EL2)
The CNTHVS_TVAL_EL2 characteristics are:
Purpose
Holds the timer value for the Secure EL2 virtual timer.
Configuration
AArch64 System register CNTHVS_TVAL_EL2 bits [31:0] are architecturally mapped to AArch32 System register CNTHVS_TVAL[31:0] .
This register is present only when EL2 is implemented and FEAT_SEL2 is implemented. Otherwise, direct accesses to CNTHVS_TVAL_EL2 are UNDEFINED.
Attributes
CNTHVS_TVAL_EL2 is a 64-bit register.
Field descriptions
The CNTHVS_TVAL_EL2 bit assignments are:
| 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 |
| RES0 | |||||||||||||||||||||||||||||||
| TimerValue | |||||||||||||||||||||||||||||||
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Bits [63:32]
Reserved, RES0.
TimerValue, bits [31:0]
The TimerValue view of the EL2 virtual timer.
On a read of this register:
- If CNTHVS_CTL_EL2.ENABLE is 0, the value returned is UNKNOWN.
- If CNTHVS_CTL_EL2.ENABLE is 1, the value returned is (CNTHVS_CVAL_EL2 - CNTVCT_EL0).
On a write of this register, CNTHVS_CVAL_EL2 is set to (CNTVCT_EL0 + TimerValue), where TimerValue is treated as a signed 32-bit integer.
When CNTHVS_CTL_EL2.ENABLE is 1, the timer condition is met when ((CNTVCT_EL0 - CNTHVS_CVAL_EL2) is greater than or equal to zero. This means that TimerValue acts like a 32-bit downcounter timer. When the timer condition is met:
- CNTHVS_CTL_EL2.ISTATUS is set to 1.
- If CNTHVS_CTL_EL2.IMASK is 0, an interrupt is generated.
When CNTHVS_CTL_EL2.ENABLE is 0, the timer condition is not met, but CNTVCT_EL0 continues to count, so the TimerValue view appears to continue to count down.
This field resets to an architecturally UNKNOWN value.
Accessing the CNTHVS_TVAL_EL2
Accesses to this register use the following encodings:
MRS <Xt>, CNTHVS_TVAL_EL2
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b100 | 0b1110 | 0b0100 | 0b000 |
if PSTATE.EL == EL0 then
UNDEFINED;
elsif PSTATE.EL == EL1 then
if HaveEL(EL3) && SCR_EL3.NS == '1' then
UNDEFINED;
elsif EL2Enabled() && HCR_EL2.NV == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
UNDEFINED;
elsif PSTATE.EL == EL2 then
if HaveEL(EL3) && SCR_EL3.NS == '1' then
UNDEFINED;
else
return CNTHVS_TVAL_EL2;
elsif PSTATE.EL == EL3 then
if SCR_EL3.EEL2 == '0' then
UNDEFINED;
else
return CNTHVS_TVAL_EL2;
MSR CNTHVS_TVAL_EL2, <Xt>
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b100 | 0b1110 | 0b0100 | 0b000 |
if PSTATE.EL == EL0 then
UNDEFINED;
elsif PSTATE.EL == EL1 then
if HaveEL(EL3) && SCR_EL3.NS == '1' then
UNDEFINED;
elsif EL2Enabled() && HCR_EL2.NV == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
UNDEFINED;
elsif PSTATE.EL == EL2 then
if HaveEL(EL3) && SCR_EL3.NS == '1' then
UNDEFINED;
else
CNTHVS_TVAL_EL2 = X[t];
elsif PSTATE.EL == EL3 then
if SCR_EL3.EEL2 == '0' then
UNDEFINED;
else
CNTHVS_TVAL_EL2 = X[t];
MRS <Xt>, CNTV_TVAL_EL0
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b011 | 0b1110 | 0b0011 | 0b000 |
if PSTATE.EL == EL0 then
if !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VTEN == '0' then
if EL2Enabled() && HCR_EL2.TGE == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
AArch64.SystemAccessTrap(EL1, 0x18);
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0VTEN == '0' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> != '11' && CNTHCTL_EL2.EL1TVT == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' && IsFeatureImplemented("FEAT_SEL2") then
return CNTHVS_TVAL_EL2;
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then
return CNTHV_TVAL_EL2;
else
return CNTV_TVAL_EL0;
elsif PSTATE.EL == EL1 then
if EL2Enabled() && CNTHCTL_EL2.EL1TVT == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
return CNTV_TVAL_EL0;
elsif PSTATE.EL == EL2 then
if HCR_EL2.E2H == '1' && SCR_EL3.NS == '0' && IsFeatureImplemented("FEAT_SEL2") then
return CNTHVS_TVAL_EL2;
elsif HCR_EL2.E2H == '1' && SCR_EL3.NS == '1' then
return CNTHV_TVAL_EL2;
else
return CNTV_TVAL_EL0;
elsif PSTATE.EL == EL3 then
return CNTV_TVAL_EL0;
MSR CNTV_TVAL_EL0, <Xt>
| op0 | op1 | CRn | CRm | op2 |
|---|---|---|---|---|
| 0b11 | 0b011 | 0b1110 | 0b0011 | 0b000 |
if PSTATE.EL == EL0 then
if !(EL2Enabled() && HCR_EL2.<E2H,TGE> == '11') && CNTKCTL_EL1.EL0VTEN == '0' then
if EL2Enabled() && HCR_EL2.TGE == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
AArch64.SystemAccessTrap(EL1, 0x18);
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> == '11' && CNTHCTL_EL2.EL0VTEN == '0' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> != '11' && CNTHCTL_EL2.EL1TVT == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '0' && IsFeatureImplemented("FEAT_SEL2") then
CNTHVS_TVAL_EL2 = X[t];
elsif EL2Enabled() && HCR_EL2.<E2H,TGE> == '11' && SCR_EL3.NS == '1' then
CNTHV_TVAL_EL2 = X[t];
else
CNTV_TVAL_EL0 = X[t];
elsif PSTATE.EL == EL1 then
if EL2Enabled() && CNTHCTL_EL2.EL1TVT == '1' then
AArch64.SystemAccessTrap(EL2, 0x18);
else
CNTV_TVAL_EL0 = X[t];
elsif PSTATE.EL == EL2 then
if HCR_EL2.E2H == '1' && SCR_EL3.NS == '0' && IsFeatureImplemented("FEAT_SEL2") then
CNTHVS_TVAL_EL2 = X[t];
elsif HCR_EL2.E2H == '1' && SCR_EL3.NS == '1' then
CNTHV_TVAL_EL2 = X[t];
else
CNTV_TVAL_EL0 = X[t];
elsif PSTATE.EL == EL3 then
CNTV_TVAL_EL0 = X[t];