diff mbox series

[kvm-unit-tests,v2] configure: arm/arm64: Add --earlycon option to set UART type and address

Message ID 20210318162022.84482-1-alexandru.elisei@arm.com (mailing list archive)
State New, archived
Headers show
Series [kvm-unit-tests,v2] configure: arm/arm64: Add --earlycon option to set UART type and address | expand

Commit Message

Alexandru Elisei March 18, 2021, 4:20 p.m. UTC
Currently, the UART early address is set indirectly with the --vmm option
and there are only two possible values: if the VMM is qemu (the default),
then the UART address is set to 0x09000000; if the VMM is kvmtool, then the
UART address is set to 0x3f8.

The upstream kvmtool commit 45b4968e0de1 ("hw/serial: ARM/arm64: Use MMIO
at higher addresses") changed the UART address to 0x1000000, and
kvm-unit-tests so far hasn't had mechanism to let the user set a specific
address, which means that for recent versions of kvmtool the early UART
won't be available.

This situation will only become worse as kvm-unit-tests gains support to
run as an EFI app, as each platform will have their own UART type and
address.

To address both issues, a new configure option is added, --earlycon. The
syntax and semantics are identical to the kernel parameter with the same
name. For example, for kvmtool, --earlycon=uart,mmio,0x1000000 will set the
correct UART address. Specifying this option will overwrite the UART
address set by --vmm.

At the moment, the UART type and register width parameters are ignored
since both qemu's and kvmtool's UART emulation use the same offset for the
TX register and no other registers are used by kvm-unit-tests, but the
parameters will become relevant once EFI support is added.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
Besides working with current versions of kvmtool, this will also make early
console work if the user specifies a custom memory layout [1] (patches are
old, but I plan to pick them up at some point in the future).

Changes in v2:
* kvmtool patches were merged, so I reworked the commit message to point to
  the corresponding kvmtool commit.
* Restricted pl011 register size to 32 bits, as per Arm Base System
  Architecture 1.0 (DEN0094A), and to match Linux.
* Reworked the way the fields are extracted to make it more precise
  (without the -s argument, the entire string is echo'ed when no delimiter
  is found).
* The changes are not trivial, so I dropped Drew's Reviewed-by.

[1] https://lore.kernel.org/kvm/1569245722-23375-1-git-send-email-alexandru.elisei@arm.com/

 configure | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

Comments

Andrew Jones March 18, 2021, 4:41 p.m. UTC | #1
On Thu, Mar 18, 2021 at 04:20:22PM +0000, Alexandru Elisei wrote:
> Currently, the UART early address is set indirectly with the --vmm option
> and there are only two possible values: if the VMM is qemu (the default),
> then the UART address is set to 0x09000000; if the VMM is kvmtool, then the
> UART address is set to 0x3f8.
> 
> The upstream kvmtool commit 45b4968e0de1 ("hw/serial: ARM/arm64: Use MMIO
> at higher addresses") changed the UART address to 0x1000000, and
> kvm-unit-tests so far hasn't had mechanism to let the user set a specific
> address, which means that for recent versions of kvmtool the early UART
> won't be available.
> 
> This situation will only become worse as kvm-unit-tests gains support to
> run as an EFI app, as each platform will have their own UART type and
> address.
> 
> To address both issues, a new configure option is added, --earlycon. The
> syntax and semantics are identical to the kernel parameter with the same
> name. For example, for kvmtool, --earlycon=uart,mmio,0x1000000 will set the
> correct UART address. Specifying this option will overwrite the UART
> address set by --vmm.
> 
> At the moment, the UART type and register width parameters are ignored
> since both qemu's and kvmtool's UART emulation use the same offset for the
> TX register and no other registers are used by kvm-unit-tests, but the
> parameters will become relevant once EFI support is added.
> 
> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
> ---
> Besides working with current versions of kvmtool, this will also make early
> console work if the user specifies a custom memory layout [1] (patches are
> old, but I plan to pick them up at some point in the future).
> 
> Changes in v2:
> * kvmtool patches were merged, so I reworked the commit message to point to
>   the corresponding kvmtool commit.
> * Restricted pl011 register size to 32 bits, as per Arm Base System
>   Architecture 1.0 (DEN0094A), and to match Linux.
> * Reworked the way the fields are extracted to make it more precise
>   (without the -s argument, the entire string is echo'ed when no delimiter
>   is found).

You can also drop 'cut' and just do something like

IFS=, read -r name type_addr addr <<<"$earlycon"

> * The changes are not trivial, so I dropped Drew's Reviewed-by.
> 
> [1] https://lore.kernel.org/kvm/1569245722-23375-1-git-send-email-alexandru.elisei@arm.com/
> 
>  configure | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
> 
> diff --git a/configure b/configure
> index cdcd34e94030..137b165db18f 100755
> --- a/configure
> +++ b/configure
> @@ -26,6 +26,7 @@ errata_force=0
>  erratatxt="$srcdir/errata.txt"
>  host_key_document=
>  page_size=
> +earlycon=
>  
>  usage() {
>      cat <<-EOF
> @@ -54,6 +55,18 @@ usage() {
>  	    --page-size=PAGE_SIZE
>  	                           Specify the page size (translation granule) (4k, 16k or
>  	                           64k, default is 64k, arm64 only)
> +	    --earlycon=EARLYCON
> +	                           Specify the UART name, type and address (optional, arm and
> +	                           arm64 only). The specified address will overwrite the UART
> +	                           address set by the --vmm option. EARLYCON can be on of (case

'on of' typo still here

> +	                           sensitive):
> +	               uart[8250],mmio,ADDR
> +	                           Specify an 8250 compatible UART at address ADDR. Supported
> +	                           register stride is 8 bit only.
> +	               pl011,ADDR
> +	               pl011,mmio32,ADDR
> +	                           Specify a PL011 compatible UART at address ADDR. Supported
> +	                           register stride is 32 bit only.
>  EOF
>      exit 1
>  }
> @@ -112,6 +125,9 @@ while [[ "$1" = -* ]]; do
>  	--page-size)
>  	    page_size="$arg"
>  	    ;;
> +	--earlycon)
> +	    earlycon="$arg"
> +	    ;;
>  	--help)
>  	    usage
>  	    ;;
> @@ -170,6 +186,51 @@ elif [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
>          echo '--vmm must be one of "qemu" or "kvmtool"!'
>          usage
>      fi
> +
> +    if [ "$earlycon" ]; then
> +        # Append delimiter and use cut -s to prevent cut from ignoring the field
> +        # argument if no delimiter is specified by the user.
> +        earlycon="$earlycon,"
> +        name=$(echo $earlycon|cut -sd',' -f1)
> +        if [ "$name" != "uart" ] && [ "$name" != "uart8250" ] &&
> +                [ "$name" != "pl011" ]; then
> +            echo "unknown earlycon name: $name"
> +            usage
> +        fi
> +
> +        if [ "$name" = "pl011" ]; then
> +            type_addr=$(echo $earlycon|cut -sd',' -f2)
> +            if [ -z "$type_addr" ]; then
> +                echo "missing earlycon address"
> +                usage
> +            fi
> +            addr=$(echo $earlycon|cut -sd',' -f3)
> +            if [ -z "$addr" ]; then

Don't you need

  if [ "$type_addr" = "mmio32" ]; then
     echo "missing earlycon address"
     usage
  fi

here to avoid accepting

  pl011,mmio32

and then assigning mmio32 to the address?

And/or should we do a quick sanity check on the address?
Something like

  [[ $addr =~ ^0?x?[0-9a-f]+$ ]]


> +                addr=$type_addr
> +            else
> +                if [ "$type_addr" != "mmio32" ]; then
> +                    echo "unknown $name earlycon type: $type_addr"
> +                    usage
> +                fi
> +            fi
> +        else
> +            type=$(echo $earlycon|cut -sd',' -f2)
> +            if [ -z "$type" ]; then
> +                echo "missing $name earlycon type"
> +                usage
> +            fi
> +            if [ "$type" != "mmio" ]; then
> +                echo "unknown $name earlycon type: $type"
> +                usage
> +            fi
> +            addr=$(echo $earlycon|cut -sd',' -f3)
> +            if [ -z "$addr" ]; then
> +                echo "missing earlycon address"
> +                usage
> +            fi
> +        fi
> +        arm_uart_early_addr=$addr
> +    fi
>  elif [ "$arch" = "ppc64" ]; then
>      testdir=powerpc
>      firmware="$testdir/boot_rom.bin"
> -- 
> 2.30.2
> 

Thanks,
drew
Alexandru Elisei March 19, 2021, 11:37 a.m. UTC | #2
Hi Drew,

Thanks for having another look!

On 3/18/21 4:41 PM, Andrew Jones wrote:
> On Thu, Mar 18, 2021 at 04:20:22PM +0000, Alexandru Elisei wrote:
>> Currently, the UART early address is set indirectly with the --vmm option
>> and there are only two possible values: if the VMM is qemu (the default),
>> then the UART address is set to 0x09000000; if the VMM is kvmtool, then the
>> UART address is set to 0x3f8.
>>
>> The upstream kvmtool commit 45b4968e0de1 ("hw/serial: ARM/arm64: Use MMIO
>> at higher addresses") changed the UART address to 0x1000000, and
>> kvm-unit-tests so far hasn't had mechanism to let the user set a specific
>> address, which means that for recent versions of kvmtool the early UART
>> won't be available.
>>
>> This situation will only become worse as kvm-unit-tests gains support to
>> run as an EFI app, as each platform will have their own UART type and
>> address.
>>
>> To address both issues, a new configure option is added, --earlycon. The
>> syntax and semantics are identical to the kernel parameter with the same
>> name. For example, for kvmtool, --earlycon=uart,mmio,0x1000000 will set the
>> correct UART address. Specifying this option will overwrite the UART
>> address set by --vmm.
>>
>> At the moment, the UART type and register width parameters are ignored
>> since both qemu's and kvmtool's UART emulation use the same offset for the
>> TX register and no other registers are used by kvm-unit-tests, but the
>> parameters will become relevant once EFI support is added.
>>
>> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
>> ---
>> Besides working with current versions of kvmtool, this will also make early
>> console work if the user specifies a custom memory layout [1] (patches are
>> old, but I plan to pick them up at some point in the future).
>>
>> Changes in v2:
>> * kvmtool patches were merged, so I reworked the commit message to point to
>>   the corresponding kvmtool commit.
>> * Restricted pl011 register size to 32 bits, as per Arm Base System
>>   Architecture 1.0 (DEN0094A), and to match Linux.
>> * Reworked the way the fields are extracted to make it more precise
>>   (without the -s argument, the entire string is echo'ed when no delimiter
>>   is found).
> You can also drop 'cut' and just do something like
>
> IFS=, read -r name type_addr addr <<<"$earlycon"

That looks much nicer and concise, and I prefer it to my approach.

However, I believe it requires a certain version of bash to work. On bash 5.1.4
and 4.3.48 (copyright says it's from 2013), it works as expected. On bash 3.2.57
(version used by MacOS), the result of the command is that the variable name
contains the string with the comma replaced by space, and the other variables are
empty. Using cut works with this version. According to the copyright notice, bash
3.2.57 is from 2007, so extremely old.

Did some googling for the query "bash split string" and according to this stack
overflow question [1] (second reply), using IFS works for bash >= 4.2. Don't know
how accurate it is.

I guess the question here is how compatible we want to be with regard to the bash
version. I am not familiar with bash programming, so I will defer to your decision.

[1]
https://stackoverflow.com/questions/918886/how-do-i-split-a-string-on-a-delimiter-in-bash

>
>> * The changes are not trivial, so I dropped Drew's Reviewed-by.
>>
>> [1] https://lore.kernel.org/kvm/1569245722-23375-1-git-send-email-alexandru.elisei@arm.com/
>>
>>  configure | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 61 insertions(+)
>>
>> diff --git a/configure b/configure
>> index cdcd34e94030..137b165db18f 100755
>> --- a/configure
>> +++ b/configure
>> @@ -26,6 +26,7 @@ errata_force=0
>>  erratatxt="$srcdir/errata.txt"
>>  host_key_document=
>>  page_size=
>> +earlycon=
>>  
>>  usage() {
>>      cat <<-EOF
>> @@ -54,6 +55,18 @@ usage() {
>>  	    --page-size=PAGE_SIZE
>>  	                           Specify the page size (translation granule) (4k, 16k or
>>  	                           64k, default is 64k, arm64 only)
>> +	    --earlycon=EARLYCON
>> +	                           Specify the UART name, type and address (optional, arm and
>> +	                           arm64 only). The specified address will overwrite the UART
>> +	                           address set by the --vmm option. EARLYCON can be on of (case
> 'on of' typo still here

Sorry, I missed that in your previous comment.

>
>> +	                           sensitive):
>> +	               uart[8250],mmio,ADDR
>> +	                           Specify an 8250 compatible UART at address ADDR. Supported
>> +	                           register stride is 8 bit only.
>> +	               pl011,ADDR
>> +	               pl011,mmio32,ADDR
>> +	                           Specify a PL011 compatible UART at address ADDR. Supported
>> +	                           register stride is 32 bit only.
>>  EOF
>>      exit 1
>>  }
>> @@ -112,6 +125,9 @@ while [[ "$1" = -* ]]; do
>>  	--page-size)
>>  	    page_size="$arg"
>>  	    ;;
>> +	--earlycon)
>> +	    earlycon="$arg"
>> +	    ;;
>>  	--help)
>>  	    usage
>>  	    ;;
>> @@ -170,6 +186,51 @@ elif [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
>>          echo '--vmm must be one of "qemu" or "kvmtool"!'
>>          usage
>>      fi
>> +
>> +    if [ "$earlycon" ]; then
>> +        # Append delimiter and use cut -s to prevent cut from ignoring the field
>> +        # argument if no delimiter is specified by the user.
>> +        earlycon="$earlycon,"
>> +        name=$(echo $earlycon|cut -sd',' -f1)
>> +        if [ "$name" != "uart" ] && [ "$name" != "uart8250" ] &&
>> +                [ "$name" != "pl011" ]; then
>> +            echo "unknown earlycon name: $name"
>> +            usage
>> +        fi
>> +
>> +        if [ "$name" = "pl011" ]; then
>> +            type_addr=$(echo $earlycon|cut -sd',' -f2)
>> +            if [ -z "$type_addr" ]; then
>> +                echo "missing earlycon address"
>> +                usage
>> +            fi
>> +            addr=$(echo $earlycon|cut -sd',' -f3)
>> +            if [ -z "$addr" ]; then
> Don't you need
>
>   if [ "$type_addr" = "mmio32" ]; then
>      echo "missing earlycon address"
>      usage
>   fi
>
> here to avoid accepting
>
>   pl011,mmio32
>
> and then assigning mmio32 to the address?

That's a good idea.

>
> And/or should we do a quick sanity check on the address?
> Something like
>
>   [[ $addr =~ ^0?x?[0-9a-f]+$ ]]

Another great suggestion. The pattern above doesn't take into account character
case and the fact that 0xa is a valid number, but a is not. Best I could come up
with is:

[[ $addr =~ ^0(x|X)[0-9a-fA-F]+$ ]] || [[ $addr =~ ^[0-9]+$ ]]

What do you think?

Thanks,

Alex

>
>
>> +                addr=$type_addr
>> +            else
>> +                if [ "$type_addr" != "mmio32" ]; then
>> +                    echo "unknown $name earlycon type: $type_addr"
>> +                    usage
>> +                fi
>> +            fi
>> +        else
>> +            type=$(echo $earlycon|cut -sd',' -f2)
>> +            if [ -z "$type" ]; then
>> +                echo "missing $name earlycon type"
>> +                usage
>> +            fi
>> +            if [ "$type" != "mmio" ]; then
>> +                echo "unknown $name earlycon type: $type"
>> +                usage
>> +            fi
>> +            addr=$(echo $earlycon|cut -sd',' -f3)
>> +            if [ -z "$addr" ]; then
>> +                echo "missing earlycon address"
>> +                usage
>> +            fi
>> +        fi
>> +        arm_uart_early_addr=$addr
>> +    fi
>>  elif [ "$arch" = "ppc64" ]; then
>>      testdir=powerpc
>>      firmware="$testdir/boot_rom.bin"
>> -- 
>> 2.30.2
>>
> Thanks,
> drew
>
Andrew Jones March 19, 2021, 11:57 a.m. UTC | #3
On Fri, Mar 19, 2021 at 11:37:51AM +0000, Alexandru Elisei wrote:
> > You can also drop 'cut' and just do something like
> >
> > IFS=, read -r name type_addr addr <<<"$earlycon"
> 
> That looks much nicer and concise, and I prefer it to my approach.
> 
> However, I believe it requires a certain version of bash to work. On bash 5.1.4
> and 4.3.48 (copyright says it's from 2013), it works as expected. On bash 3.2.57
> (version used by MacOS), the result of the command is that the variable name
> contains the string with the comma replaced by space, and the other variables are
> empty. Using cut works with this version. According to the copyright notice, bash
> 3.2.57 is from 2007, so extremely old.
> 
> Did some googling for the query "bash split string" and according to this stack
> overflow question [1] (second reply), using IFS works for bash >= 4.2. Don't know
> how accurate it is.
> 
> I guess the question here is how compatible we want to be with regard to the bash
> version. I am not familiar with bash programming, so I will defer to your decision.

From time to time we've had this come up with kvm-unit-tests. The result
has always been to say "yeah, we should figure out our minimally required
Bash version and document that", but then we never do... It sounds like
you've identified Bash 4.2 being required for this IFS idiom. As we
already use this idiom in other places in kvm-unit-tests, then I think
the right thing to do is to test running all the current scripts with
Bash 4.2, and if that works, finally document it. I'll do that ASAP.

> > And/or should we do a quick sanity check on the address?
> > Something like
> >
> >   [[ $addr =~ ^0?x?[0-9a-f]+$ ]]
> 
> Another great suggestion. The pattern above doesn't take into account character
> case and the fact that 0xa is a valid number, but a is not. Best I could come up
> with is:
> 
> [[ $addr =~ ^0(x|X)[0-9a-fA-F]+$ ]] || [[ $addr =~ ^[0-9]+$ ]]
> 
> What do you think?

LGTM

Thanks,
drew
diff mbox series

Patch

diff --git a/configure b/configure
index cdcd34e94030..137b165db18f 100755
--- a/configure
+++ b/configure
@@ -26,6 +26,7 @@  errata_force=0
 erratatxt="$srcdir/errata.txt"
 host_key_document=
 page_size=
+earlycon=
 
 usage() {
     cat <<-EOF
@@ -54,6 +55,18 @@  usage() {
 	    --page-size=PAGE_SIZE
 	                           Specify the page size (translation granule) (4k, 16k or
 	                           64k, default is 64k, arm64 only)
+	    --earlycon=EARLYCON
+	                           Specify the UART name, type and address (optional, arm and
+	                           arm64 only). The specified address will overwrite the UART
+	                           address set by the --vmm option. EARLYCON can be on of (case
+	                           sensitive):
+	               uart[8250],mmio,ADDR
+	                           Specify an 8250 compatible UART at address ADDR. Supported
+	                           register stride is 8 bit only.
+	               pl011,ADDR
+	               pl011,mmio32,ADDR
+	                           Specify a PL011 compatible UART at address ADDR. Supported
+	                           register stride is 32 bit only.
 EOF
     exit 1
 }
@@ -112,6 +125,9 @@  while [[ "$1" = -* ]]; do
 	--page-size)
 	    page_size="$arg"
 	    ;;
+	--earlycon)
+	    earlycon="$arg"
+	    ;;
 	--help)
 	    usage
 	    ;;
@@ -170,6 +186,51 @@  elif [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then
         echo '--vmm must be one of "qemu" or "kvmtool"!'
         usage
     fi
+
+    if [ "$earlycon" ]; then
+        # Append delimiter and use cut -s to prevent cut from ignoring the field
+        # argument if no delimiter is specified by the user.
+        earlycon="$earlycon,"
+        name=$(echo $earlycon|cut -sd',' -f1)
+        if [ "$name" != "uart" ] && [ "$name" != "uart8250" ] &&
+                [ "$name" != "pl011" ]; then
+            echo "unknown earlycon name: $name"
+            usage
+        fi
+
+        if [ "$name" = "pl011" ]; then
+            type_addr=$(echo $earlycon|cut -sd',' -f2)
+            if [ -z "$type_addr" ]; then
+                echo "missing earlycon address"
+                usage
+            fi
+            addr=$(echo $earlycon|cut -sd',' -f3)
+            if [ -z "$addr" ]; then
+                addr=$type_addr
+            else
+                if [ "$type_addr" != "mmio32" ]; then
+                    echo "unknown $name earlycon type: $type_addr"
+                    usage
+                fi
+            fi
+        else
+            type=$(echo $earlycon|cut -sd',' -f2)
+            if [ -z "$type" ]; then
+                echo "missing $name earlycon type"
+                usage
+            fi
+            if [ "$type" != "mmio" ]; then
+                echo "unknown $name earlycon type: $type"
+                usage
+            fi
+            addr=$(echo $earlycon|cut -sd',' -f3)
+            if [ -z "$addr" ]; then
+                echo "missing earlycon address"
+                usage
+            fi
+        fi
+        arm_uart_early_addr=$addr
+    fi
 elif [ "$arch" = "ppc64" ]; then
     testdir=powerpc
     firmware="$testdir/boot_rom.bin"