CNTHVS_CVAL, Counter-timer Secure Virtual Timer CompareValue Register (EL2)

The CNTHVS_CVAL characteristics are:

Purpose

Provides AArch32 access to the compare value for the Secure EL2 virtual timer.

Configuration

AArch32 System register CNTHVS_CVAL bits [63:0] are architecturally mapped to AArch64 System register CNTHVS_CVAL_EL2[63:0].

This register is present only when AArch32 is supported and FEAT_SEL2 is implemented. Otherwise, direct accesses to CNTHVS_CVAL are UNDEFINED.

Attributes

CNTHVS_CVAL is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
CompareValue
CompareValue

CompareValue, bits [63:0]

Holds the EL2 virtual timer CompareValue.

When CNTHVS_CTL.ENABLE is 1, the timer condition is met when (CNTVCT - CompareValue) is greater than or equal to zero. This means that CompareValue acts like a 64-bit upcounter timer. When the timer condition is met:

When CNTHVS_CTL.ENABLE is 0, the timer condition is not met, but CNTVCT continues to count.

If the Generic counter is implemented at a size less than 64 bits, then this field is permitted to be implemented at the same width as the counter, and the upper bits are RES0.

The value of this field is treated as zero-extended in all counter calculations.

Accessing CNTHVS_CVAL

This register is accessed using the encoding for CNTV_CVAL.

Accesses to this register use the following encodings in the System register encoding space:

MRRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>

coprocCRmopc1
0b11110b11100b0011

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !ELIsInHost(EL0) && CNTKCTL_EL1.EL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else AArch64.AArch32SystemAccessTrap(EL1, 0x04); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif ELIsInHost(EL0) && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && !ELIsInHost(EL0) && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif ELIsInHost(EL0) && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then (R[t2], R[t]) = (CNTHVS_CVAL_EL2<63:32>, CNTHVS_CVAL_EL2<31:0>); elsif ELIsInHost(EL0) && !IsCurrentSecurityState(SS_Secure) then (R[t2], R[t]) = (CNTHV_CVAL_EL2<63:32>, CNTHV_CVAL_EL2<31:0>); else (R[t2], R[t]) = (CNTV_CVAL<63:32>, CNTV_CVAL<31:0>); elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else (R[t2], R[t]) = (CNTV_CVAL<63:32>, CNTV_CVAL<31:0>); elsif PSTATE.EL == EL2 then (R[t2], R[t]) = (CNTV_CVAL<63:32>, CNTV_CVAL<31:0>); elsif PSTATE.EL == EL3 then (R[t2], R[t]) = (CNTV_CVAL<63:32>, CNTV_CVAL<31:0>);

MCRR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <Rt2>, <CRm>

coprocCRmopc1
0b11110b11100b0011

if PSTATE.EL == EL0 then if !ELUsingAArch32(EL1) && !ELIsInHost(EL0) && CNTKCTL_EL1.EL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else AArch64.AArch32SystemAccessTrap(EL1, 0x04); elsif ELUsingAArch32(EL1) && CNTKCTL.PL0VTEN == '0' then if EL2Enabled() && !ELUsingAArch32(EL2) && HCR_EL2.TGE == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && ELUsingAArch32(EL2) && HCR.TGE == '1' then AArch32.TakeHypTrapException(0x00); else UNDEFINED; elsif ELIsInHost(EL0) && CNTHCTL_EL2.EL0VTEN == '0' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif EL2Enabled() && !ELUsingAArch32(EL2) && !ELIsInHost(EL0) && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); elsif ELIsInHost(EL0) && IsCurrentSecurityState(SS_Secure) && IsFeatureImplemented(FEAT_SEL2) then CNTHVS_CVAL_EL2 = R[t2]:R[t]; elsif ELIsInHost(EL0) && !IsCurrentSecurityState(SS_Secure) then CNTHV_CVAL_EL2 = R[t2]:R[t]; else CNTV_CVAL = R[t2]:R[t]; elsif PSTATE.EL == EL1 then if EL2Enabled() && !ELUsingAArch32(EL2) && IsFeatureImplemented(FEAT_ECV) && CNTHCTL_EL2.EL1TVT == '1' then AArch64.AArch32SystemAccessTrap(EL2, 0x04); else CNTV_CVAL = R[t2]:R[t]; elsif PSTATE.EL == EL2 then CNTV_CVAL = R[t2]:R[t]; elsif PSTATE.EL == EL3 then CNTV_CVAL = R[t2]:R[t];


26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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