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iommu/amd: Clean up RMP entries for IOMMU pages during SNP shutdown

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Add a new IOMMU API interface amd_iommu_snp_disable() to transition
IOMMU pages to Hypervisor state from Reclaim state after SNP_SHUTDOWN_EX
command. Invoke this API from the CCP driver after SNP_SHUTDOWN_EX
command.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240126041126.1927228-20-michael.roth@amd.com
This commit is contained in:
Ashish Kalra
2024-01-25 22:11:19 -06:00
committed by Borislav Petkov (AMD)
parent a867ad6b34
commit f366a8dac1
3 changed files with 105 additions and 0 deletions
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20
drivers/crypto/ccp/sev-dev.c
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@@ -26,6 +26,7 @@
#include <linux/fs.h>
#include <linux/fs_struct.h>
#include <linux/psp.h>
#include <linux/amd-iommu.h>
#include <asm/smp.h>
#include <asm/cacheflush.h>
@@ -1655,6 +1656,25 @@ static int __sev_snp_shutdown_locked(int *error)
return ret;
}
/*
* SNP_SHUTDOWN_EX with IOMMU_SNP_SHUTDOWN set to 1 disables SNP
* enforcement by the IOMMU and also transitions all pages
* associated with the IOMMU to the Reclaim state.
* Firmware was transitioning the IOMMU pages to Hypervisor state
* before version 1.53. But, accounting for the number of assigned
* 4kB pages in a 2M page was done incorrectly by not transitioning
* to the Reclaim state. This resulted in RMP #PF when later accessing
* the 2M page containing those pages during kexec boot. Hence, the
* firmware now transitions these pages to Reclaim state and hypervisor
* needs to transition these pages to shared state. SNP Firmware
* version 1.53 and above are needed for kexec boot.
*/
ret = amd_iommu_snp_disable();
if (ret) {
dev_err(sev->dev, "SNP IOMMU shutdown failed\n");
return ret;
}
sev->snp_initialized = false;
dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");