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[0/2,l,linux-azure] Azure: Update TDX with HCL support

Message ID 20231031131909.99632-1-tim.gardner@canonical.com
Headers show
Series Azure: Update TDX with HCL support | expand

Message

Tim Gardner Oct. 31, 2023, 1:19 p.m. UTC 
BugLink: https://bugs.launchpad.net/bugs/2042096

SRU Justification

[Impact]

Microsoft has asked for the addition of 2 patches for TDX and SNP-SEV VM support with HCL.

The refreshed patches will fix 2 bugs for future Hyper-V versions:
1) PCI DDA for Linux TDX VMs with HCL is not working due to a guest bug and a host bug.
The guest bug is fixed in the mainline version of the TDX patches.
2) On a recent Hyper-V dev build that advertises the Hyper-V TLB flushing hypercalls,
the current Ubuntu 6.2 kernel passes a shared input page to the Hyper-V while it should
pass a private input page; as a result, the hypercall always fails and Linux now falls
back to the legacy native method of flusing TLB. This slows down the flush-TLB
operation . The mainline version doesn't have the bug.

[Test Plan]

Microsoft tested.

[Regression Potential]

Azure instances with TDX on HCL hypervisors may not work correctly.

[Other Info]

SF: #00364214

Comments

Cengiz Can Oct. 31, 2023, 3:17 p.m. UTC | #1 
On Tue, 2023-10-31 at 07:19 -0600, Tim Gardner wrote:
> BugLink: https://bugs.launchpad.net/bugs/2042096
> 
> SRU Justification
> 
> [Impact]
> 
> Microsoft has asked for the addition of 2 patches for TDX and SNP-SEV
> VM support with HCL.
> 
> The refreshed patches will fix 2 bugs for future Hyper-V versions:
> 1) PCI DDA for Linux TDX VMs with HCL is not working due to a guest
> bug and a host bug.
> The guest bug is fixed in the mainline version of the TDX patches.
> 2) On a recent Hyper-V dev build that advertises the Hyper-V TLB
> flushing hypercalls,
> the current Ubuntu 6.2 kernel passes a shared input page to the
> Hyper-V while it should
> pass a private input page; as a result, the hypercall always fails
> and Linux now falls
> back to the legacy native method of flusing TLB. This slows down the
> flush-TLB
> operation . The mainline version doesn't have the bug.
> 
> [Test Plan]
> 
> Microsoft tested.
> 
> [Regression Potential]
> 
> Azure instances with TDX on HCL hypervisors may not work correctly.

Acked-by: Cengiz Can <cengiz.can@canonical.com>

> 
> [Other Info]
> 
> SF: #00364214
> 
>
Philip Cox Oct. 31, 2023, 4:48 p.m. UTC | #2 
On Tue, 2023-10-31 at 07:19 -0600, Tim Gardner wrote:
> BugLink: https://bugs.launchpad.net/bugs/2042096
> 
> SRU Justification
> 
> [Impact]
> 
> Microsoft has asked for the addition of 2 patches for TDX and SNP-SEV
> VM support with HCL.
> 
> The refreshed patches will fix 2 bugs for future Hyper-V versions:
> 1) PCI DDA for Linux TDX VMs with HCL is not working due to a guest
> bug and a host bug.
> The guest bug is fixed in the mainline version of the TDX patches.
> 2) On a recent Hyper-V dev build that advertises the Hyper-V TLB
> flushing hypercalls,
> the current Ubuntu 6.2 kernel passes a shared input page to the
> Hyper-V while it should
> pass a private input page; as a result, the hypercall always fails
> and Linux now falls
> back to the legacy native method of flusing TLB. This slows down the
> flush-TLB
> operation . The mainline version doesn't have the bug.
> 
> [Test Plan]
> 
> Microsoft tested.
> 
> [Regression Potential]
> 
> Azure instances with TDX on HCL hypervisors may not work correctly.
> 
> [Other Info]
> 
> SF: #00364214
> 
>
Tim Gardner Nov. 17, 2023, 5:01 p.m. UTC | #3 
On 10/31/23 7:19 AM, Tim Gardner wrote:
> BugLink: https://bugs.launchpad.net/bugs/2042096
> 
> SRU Justification
> 
> [Impact]
> 
> Microsoft has asked for the addition of 2 patches for TDX and SNP-SEV VM support with HCL.
> 
> The refreshed patches will fix 2 bugs for future Hyper-V versions:
> 1) PCI DDA for Linux TDX VMs with HCL is not working due to a guest bug and a host bug.
> The guest bug is fixed in the mainline version of the TDX patches.
> 2) On a recent Hyper-V dev build that advertises the Hyper-V TLB flushing hypercalls,
> the current Ubuntu 6.2 kernel passes a shared input page to the Hyper-V while it should
> pass a private input page; as a result, the hypercall always fails and Linux now falls
> back to the legacy native method of flusing TLB. This slows down the flush-TLB
> operation . The mainline version doesn't have the bug.
> 
> [Test Plan]
> 
> Microsoft tested.
> 
> [Regression Potential]
> 
> Azure instances with TDX on HCL hypervisors may not work correctly.
> 
> [Other Info]
> 
> SF: #00364214
> 
Applied to lunar/linux-azure:master-next. Thanks.

-rtg