| Message ID | 579bf2ec37edcfa6208f9220588a98327d832fd4.1411604443.git.geoff@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
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Hi Geoff, On Thu, Sep 25, 2014 at 01:23:26AM +0100, Geoff Levand wrote: > To allow for additional hcalls to be defined and to make the arm64 hcall API > more consistent across exception vector routines change the hcall implementations > to use the ISS field of the ESR_EL2 register to specify the hcall type. > > The existing arm64 hcall implementations are limited in that they only allow > for two distinct hcalls; with the x0 register either zero, or not zero. Also, > the API of the hyp-stub exception vector routines and the KVM exception vector > routines differ; hyp-stub uses a non-zero value in x0 to implement > __hyp_set_vectors, whereas KVM uses it to implement kvm_call_hyp. > > Define three new preprocessor macros HVC_GET_VECTORS, HVC_SET_VECTORS and > HVC_CALL_HYP and to be used as hcall type specifiers and convert the > existing __hyp_get_vectors(), __hyp_set_vectors() and kvm_call_hyp() routines > to use these new macros when executing and HVC call. Also change the > corresponding hyp-stub and KVM el1_sync exception vector routines to use these > new macros. I'm definitely in favour of using the HVC immediate. I just have some comments on the mechanics below. > Signed-off-by: Geoff Levand <geoff@infradead.org> > --- > arch/arm64/include/asm/virt.h | 20 ++++++++++++++++++++ > arch/arm64/kernel/hyp-stub.S | 33 +++++++++++++++++++++------------ > arch/arm64/kvm/hyp.S | 18 +++++++++++------- > 3 files changed, 52 insertions(+), 19 deletions(-) > > diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h > index 7a5df52..99c319c 100644 > --- a/arch/arm64/include/asm/virt.h > +++ b/arch/arm64/include/asm/virt.h > @@ -21,6 +21,26 @@ > #define BOOT_CPU_MODE_EL1 (0xe11) > #define BOOT_CPU_MODE_EL2 (0xe12) > > +/* > + * HVC_GET_VECTORS - Return the value of the vbar_el2 register. > + */ > + > +#define HVC_GET_VECTORS 1 > + > +/* > + * HVC_SET_VECTORS - Set the value of the vbar_el2 register. > + * > + * @x0: Physical address of the new vector table. > + */ > + > +#define HVC_SET_VECTORS 2 > + > +/* > + * HVC_CALL_HYP - Execute a hyp routine. > + */ > + > +#define HVC_CALL_HYP 3 > + > #ifndef __ASSEMBLY__ > > /* > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S > index a272f33..8b39522 100644 > --- a/arch/arm64/kernel/hyp-stub.S > +++ b/arch/arm64/kernel/hyp-stub.S > @@ -53,14 +53,22 @@ ENDPROC(__hyp_stub_vectors) > .align 11 > > el1_sync: > - mrs x1, esr_el2 > - lsr x1, x1, #26 > - cmp x1, #0x16 > - b.ne 2f // Not an HVC trap > - cbz x0, 1f > - msr vbar_el2, x0 // Set vbar_el2 > + mrs x18, esr_el2 > + lsr x17, x18, #26 // x17=EC The first patch enabled kvm_arm.h macros to be used from asm. Can't we use them here? If we don't include kvm_arm.h in the hyp stub, maybe we should (ideally we'd factor common stuff out, but I can see that getting messy fast). Assuming we can use them: lsr x17, x18, #ESR_EL2_EC_SHIFT > + and x18, x18, #0xffffff // x18=ISS and x18, x18, ESR_EL2_ISS > + > + cmp x17, #0x16 cmp x17, #ESR_EL2_EC_HVC64 > + b.ne 2f // Not an HVC trap > + > + cmp x18, #HVC_GET_VECTORS > + b.ne 1f > + mrs x0, vbar_el2 > b 2f > -1: mrs x0, vbar_el2 // Return vbar_el2 > + > +1: cmp x18, #HVC_SET_VECTORS > + b.ne 2f > + msr vbar_el2, x0 > + > 2: eret > ENDPROC(el1_sync) > > @@ -100,11 +108,12 @@ ENDPROC(\label) > * initialisation entry point. > */ > > -ENTRY(__hyp_get_vectors) > - mov x0, xzr > - // fall through > ENTRY(__hyp_set_vectors) > - hvc #0 > + hvc #HVC_SET_VECTORS > ret > -ENDPROC(__hyp_get_vectors) > ENDPROC(__hyp_set_vectors) > + > +ENTRY(__hyp_get_vectors) > + hvc #HVC_GET_VECTORS > + ret > +ENDPROC(__hyp_get_vectors) > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > index b72aa9f..9607f15 100644 > --- a/arch/arm64/kvm/hyp.S > +++ b/arch/arm64/kvm/hyp.S > @@ -26,6 +26,7 @@ > #include <asm/kvm_asm.h> > #include <asm/kvm_arm.h> > #include <asm/kvm_mmu.h> > +#include <asm/virt.h> As far as I can see, virt.h only defines BOOT_CPU_MODE_EL{1,2}, which we don't use below. So I don't think we need this include. Otherwise this looks fine to me. Mark. > > #define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x) > #define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x) > @@ -1105,12 +1106,9 @@ __hyp_panic_str: > * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are > * passed in r0 and r1. > * > - * A function pointer with a value of 0 has a special meaning, and is > - * used to implement __hyp_get_vectors in the same way as in > - * arch/arm64/kernel/hyp_stub.S. > */ > ENTRY(kvm_call_hyp) > - hvc #0 > + hvc #HVC_CALL_HYP > ret > ENDPROC(kvm_call_hyp) > > @@ -1140,6 +1138,7 @@ el1_sync: // Guest trapped into EL2 > push x2, x3 > > mrs x1, esr_el2 > + and x0, x1, #ESR_EL2_ISS > lsr x2, x1, #ESR_EL2_EC_SHIFT > > cmp x2, #ESR_EL2_EC_HVC64 > @@ -1149,15 +1148,19 @@ el1_sync: // Guest trapped into EL2 > cbnz x3, el1_trap // called HVC > > /* Here, we're pretty sure the host called HVC. */ > + mov x18, x0 > pop x2, x3 > pop x0, x1 > > - /* Check for __hyp_get_vectors */ > - cbnz x0, 1f > + cmp x18, #HVC_GET_VECTORS > + b.ne 1f > mrs x0, vbar_el2 > b 2f > > -1: push lr, xzr > +1: cmp x18, #HVC_CALL_HYP > + b.ne 2f > + > + push lr, xzr > > /* > * Compute the function address in EL2, and shuffle the parameters. > @@ -1170,6 +1173,7 @@ el1_sync: // Guest trapped into EL2 > blr lr > > pop lr, xzr > + > 2: eret > > el1_trap: > -- > 1.9.1 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
Hi Mark, On Fri, 2014-10-03 at 11:51 +0100, Mark Rutland wrote: > On Thu, Sep 25, 2014 at 01:23:26AM +0100, Geoff Levand wrote: > index 7a5df52..99c319c 100644 > > --- a/arch/arm64/include/asm/virt.h > > +++ b/arch/arm64/include/asm/virt.h > > @@ -21,6 +21,26 @@ > > #define BOOT_CPU_MODE_EL1 (0xe11) > > #define BOOT_CPU_MODE_EL2 (0xe12) > > > > +/* > > + * HVC_GET_VECTORS - Return the value of the vbar_el2 register. > > + */ > > + > > +#define HVC_GET_VECTORS 1 > > + > > +/* > > + * HVC_SET_VECTORS - Set the value of the vbar_el2 register. > > + * > > + * @x0: Physical address of the new vector table. > > + */ > > + > > +#define HVC_SET_VECTORS 2 > > + > > +/* > > + * HVC_CALL_HYP - Execute a hyp routine. > > + */ > > + > > +#define HVC_CALL_HYP 3 > > + > > #ifndef __ASSEMBLY__ > > > > /* > > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S > > index a272f33..8b39522 100644 > > --- a/arch/arm64/kernel/hyp-stub.S > > +++ b/arch/arm64/kernel/hyp-stub.S > > @@ -53,14 +53,22 @@ ENDPROC(__hyp_stub_vectors) > > .align 11 > > > > el1_sync: > > - mrs x1, esr_el2 > > - lsr x1, x1, #26 > > - cmp x1, #0x16 > > - b.ne 2f // Not an HVC trap > > - cbz x0, 1f > > - msr vbar_el2, x0 // Set vbar_el2 > > + mrs x18, esr_el2 > > + lsr x17, x18, #26 // x17=EC > > The first patch enabled kvm_arm.h macros to be used from asm. Can't we > use them here? If we don't include kvm_arm.h in the hyp stub, maybe we > should (ideally we'd factor common stuff out, but I can see that getting > messy fast). I didn't want to tackle the cleanup of the headers in this patch series, and I thought it odd to include a kvm header in this core arm64 file, but maybe it is better to include kvm_arm.h and use the ESR_EL2_ macros so the values are at least easier to understand and keep track of. > Assuming we can use them: > > lsr x17, x18, #ESR_EL2_EC_SHIFT > > > + and x18, x18, #0xffffff // x18=ISS > > and x18, x18, ESR_EL2_ISS > > > + > > + cmp x17, #0x16 > > cmp x17, #ESR_EL2_EC_HVC64 > > > + b.ne 2f // Not an HVC trap > > + > > + cmp x18, #HVC_GET_VECTORS > > + b.ne 1f > > + mrs x0, vbar_el2 > > b 2f > > -1: mrs x0, vbar_el2 // Return vbar_el2 > > + > > +1: cmp x18, #HVC_SET_VECTORS > > + b.ne 2f > > + msr vbar_el2, x0 > > + > > 2: eret > > ENDPROC(el1_sync) > > > > @@ -100,11 +108,12 @@ ENDPROC(\label) > > * initialisation entry point. > > */ > > > > -ENTRY(__hyp_get_vectors) > > - mov x0, xzr > > - // fall through > > ENTRY(__hyp_set_vectors) > > - hvc #0 > > + hvc #HVC_SET_VECTORS > > ret > > -ENDPROC(__hyp_get_vectors) > > ENDPROC(__hyp_set_vectors) > > + > > +ENTRY(__hyp_get_vectors) > > + hvc #HVC_GET_VECTORS > > + ret > > +ENDPROC(__hyp_get_vectors) > > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > > index b72aa9f..9607f15 100644 > > --- a/arch/arm64/kvm/hyp.S > > +++ b/arch/arm64/kvm/hyp.S > > @@ -26,6 +26,7 @@ > > #include <asm/kvm_asm.h> > > #include <asm/kvm_arm.h> > > #include <asm/kvm_mmu.h> > > +#include <asm/virt.h> > > As far as I can see, virt.h only defines BOOT_CPU_MODE_EL{1,2}, which we > don't use below. So I don't think we need this include. We need asm/virt.h for the new HVC_ macros added to it by this patch (above)... > Otherwise this looks fine to me. > > Mark. > > > > > #define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x) > > #define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x) > > @@ -1105,12 +1106,9 @@ __hyp_panic_str: > > * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are > > * passed in r0 and r1. > > * > > - * A function pointer with a value of 0 has a special meaning, and is > > - * used to implement __hyp_get_vectors in the same way as in > > - * arch/arm64/kernel/hyp_stub.S. > > */ > > ENTRY(kvm_call_hyp) > > - hvc #0 > > + hvc #HVC_CALL_HYP > > ret > > ENDPROC(kvm_call_hyp)
[...] > > > el1_sync: > > > - mrs x1, esr_el2 > > > - lsr x1, x1, #26 > > > - cmp x1, #0x16 > > > - b.ne 2f // Not an HVC trap > > > - cbz x0, 1f > > > - msr vbar_el2, x0 // Set vbar_el2 > > > + mrs x18, esr_el2 > > > + lsr x17, x18, #26 // x17=EC > > > > The first patch enabled kvm_arm.h macros to be used from asm. Can't we > > use them here? If we don't include kvm_arm.h in the hyp stub, maybe we > > should (ideally we'd factor common stuff out, but I can see that getting > > messy fast). > > I didn't want to tackle the cleanup of the headers in this patch > series, and I thought it odd to include a kvm header in this core > arm64 file, but maybe it is better to include kvm_arm.h and use the > ESR_EL2_ macros so the values are at least easier to understand and > keep track of. I'd rather we used the mnemonics. If that involves pulling in the kvm header I'd rather we do that for the moment. [...] > > > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > > > index b72aa9f..9607f15 100644 > > > --- a/arch/arm64/kvm/hyp.S > > > +++ b/arch/arm64/kvm/hyp.S > > > @@ -26,6 +26,7 @@ > > > #include <asm/kvm_asm.h> > > > #include <asm/kvm_arm.h> > > > #include <asm/kvm_mmu.h> > > > +#include <asm/virt.h> > > > > As far as I can see, virt.h only defines BOOT_CPU_MODE_EL{1,2}, which we > > don't use below. So I don't think we need this include. > > We need asm/virt.h for the new HVC_ macros added to it by this > patch (above)... Sorry, my comment was bogus. I'd evidently confused myself when reading this. Mark.
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index 7a5df52..99c319c 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -21,6 +21,26 @@ #define BOOT_CPU_MODE_EL1 (0xe11) #define BOOT_CPU_MODE_EL2 (0xe12) +/* + * HVC_GET_VECTORS - Return the value of the vbar_el2 register. + */ + +#define HVC_GET_VECTORS 1 + +/* + * HVC_SET_VECTORS - Set the value of the vbar_el2 register. + * + * @x0: Physical address of the new vector table. + */ + +#define HVC_SET_VECTORS 2 + +/* + * HVC_CALL_HYP - Execute a hyp routine. + */ + +#define HVC_CALL_HYP 3 + #ifndef __ASSEMBLY__ /* diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index a272f33..8b39522 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -53,14 +53,22 @@ ENDPROC(__hyp_stub_vectors) .align 11 el1_sync: - mrs x1, esr_el2 - lsr x1, x1, #26 - cmp x1, #0x16 - b.ne 2f // Not an HVC trap - cbz x0, 1f - msr vbar_el2, x0 // Set vbar_el2 + mrs x18, esr_el2 + lsr x17, x18, #26 // x17=EC + and x18, x18, #0xffffff // x18=ISS + + cmp x17, #0x16 + b.ne 2f // Not an HVC trap + + cmp x18, #HVC_GET_VECTORS + b.ne 1f + mrs x0, vbar_el2 b 2f -1: mrs x0, vbar_el2 // Return vbar_el2 + +1: cmp x18, #HVC_SET_VECTORS + b.ne 2f + msr vbar_el2, x0 + 2: eret ENDPROC(el1_sync) @@ -100,11 +108,12 @@ ENDPROC(\label) * initialisation entry point. */ -ENTRY(__hyp_get_vectors) - mov x0, xzr - // fall through ENTRY(__hyp_set_vectors) - hvc #0 + hvc #HVC_SET_VECTORS ret -ENDPROC(__hyp_get_vectors) ENDPROC(__hyp_set_vectors) + +ENTRY(__hyp_get_vectors) + hvc #HVC_GET_VECTORS + ret +ENDPROC(__hyp_get_vectors) diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index b72aa9f..9607f15 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -26,6 +26,7 @@ #include <asm/kvm_asm.h> #include <asm/kvm_arm.h> #include <asm/kvm_mmu.h> +#include <asm/virt.h> #define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x) #define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x) @@ -1105,12 +1106,9 @@ __hyp_panic_str: * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are * passed in r0 and r1. * - * A function pointer with a value of 0 has a special meaning, and is - * used to implement __hyp_get_vectors in the same way as in - * arch/arm64/kernel/hyp_stub.S. */ ENTRY(kvm_call_hyp) - hvc #0 + hvc #HVC_CALL_HYP ret ENDPROC(kvm_call_hyp) @@ -1140,6 +1138,7 @@ el1_sync: // Guest trapped into EL2 push x2, x3 mrs x1, esr_el2 + and x0, x1, #ESR_EL2_ISS lsr x2, x1, #ESR_EL2_EC_SHIFT cmp x2, #ESR_EL2_EC_HVC64 @@ -1149,15 +1148,19 @@ el1_sync: // Guest trapped into EL2 cbnz x3, el1_trap // called HVC /* Here, we're pretty sure the host called HVC. */ + mov x18, x0 pop x2, x3 pop x0, x1 - /* Check for __hyp_get_vectors */ - cbnz x0, 1f + cmp x18, #HVC_GET_VECTORS + b.ne 1f mrs x0, vbar_el2 b 2f -1: push lr, xzr +1: cmp x18, #HVC_CALL_HYP + b.ne 2f + + push lr, xzr /* * Compute the function address in EL2, and shuffle the parameters. @@ -1170,6 +1173,7 @@ el1_sync: // Guest trapped into EL2 blr lr pop lr, xzr + 2: eret el1_trap:
To allow for additional hcalls to be defined and to make the arm64 hcall API more consistent across exception vector routines change the hcall implementations to use the ISS field of the ESR_EL2 register to specify the hcall type. The existing arm64 hcall implementations are limited in that they only allow for two distinct hcalls; with the x0 register either zero, or not zero. Also, the API of the hyp-stub exception vector routines and the KVM exception vector routines differ; hyp-stub uses a non-zero value in x0 to implement __hyp_set_vectors, whereas KVM uses it to implement kvm_call_hyp. Define three new preprocessor macros HVC_GET_VECTORS, HVC_SET_VECTORS and HVC_CALL_HYP and to be used as hcall type specifiers and convert the existing __hyp_get_vectors(), __hyp_set_vectors() and kvm_call_hyp() routines to use these new macros when executing and HVC call. Also change the corresponding hyp-stub and KVM el1_sync exception vector routines to use these new macros. Signed-off-by: Geoff Levand <geoff@infradead.org> --- arch/arm64/include/asm/virt.h | 20 ++++++++++++++++++++ arch/arm64/kernel/hyp-stub.S | 33 +++++++++++++++++++++------------ arch/arm64/kvm/hyp.S | 18 +++++++++++------- 3 files changed, 52 insertions(+), 19 deletions(-)